How to Sign a PDF: The Free Methods That Actually Work (No Printing, No Paid App)

CodexFuse Team · 2026-10-28T01:21:35.157Z · 15 min read

Learn how to sign a PDF for free on any device — Mac Preview, iPhone Markup, Adobe Fill & Sign, or a free web signer — and when an electronic signature is legally binding.

To sign a PDF for free, use a tool you already have: Mac Preview on a Mac, Markup on an iPhone, Adobe Acrobat Reader's Fill & Sign on Windows, or a free web signer such as SignWell. You create a signature once by drawing it, typing it, or uploading a photo of it, place it on the signature line, and save the file. No printer, no scanner, and no paid app is needed for a normal contract, form, or offer letter. If you want the signature to land in exactly the right spot first, the free Sign PDF placement planner works out the signature box size and position in millimetres, points, and percent of the page. It plans the placement only; you still sign the file itself in your own PDF app.

How do you sign a PDF for free?

Signing a PDF for free means adding your signature to the file on screen instead of printing it. Every method below follows the same four steps, and the only thing that changes is which app does the work.

1. Open the PDF in Preview on a Mac, in Markup on an iPhone, in Adobe Acrobat Reader on Windows, or in a free web signer in any browser.
2. Create your signature by drawing it with a finger, mouse, or trackpad, typing your name in a signature-style font, or uploading a photo of your handwritten signature.
3. Place the signature on the signature line, then drag it into position and resize it until it fits the space.
4. Save or download the signed file and send it back. Keep the signed copy; do not overwrite the blank original if you may need it again.

That is the whole process. The rest of this guide is about picking the right method for your device and knowing when the result counts as a legal signature. Every method below shows how to electronically sign a PDF, not a print-and-scan workaround.

Is an electronic signature legally binding?

Yes. In the United States, electronic signatures are legal and binding for nearly every business transaction under the Electronic Signatures in Global and National Commerce (ESIGN) Act and the Uniform Electronic Transactions Act (UETA). DocuSign states this directly in its signing guide, updated in April 2026, and notes that its service complies with both laws.

Two conditions do most of the legal work. First, both sides must agree to do business electronically; nobody can be forced into an e-signature. Second, the signer must clearly intend to sign, which is why a real signing flow records who signed, when they signed, and what they signed. SignWell, for example, attaches an audit trail to each completed document with names, email addresses, IP information, and timestamps, and locks the finished PDF with a digital certificate so it cannot be altered afterwards.

An electronic signature and a digital signature are not the same thing, even though the terms are often swapped. An electronic signature is any symbol or data attached to a document with the intent to sign, most often an image of a handwritten signature. A digital signature is a type of electronic signature that uses encryption to verify that the signer is who they claim to be. For everyday contracts, forms, and offer letters, a standard electronic signature is enough; the encrypted kind matters when a transaction needs proof of identity built into the file itself.

How to sign a PDF on a Mac

Use Preview, the app that already opens your PDFs. Open the file in Preview, click the Markup toolbar button (the pencil icon), then click the Sign button, which looks like a small signature. If you have never signed before, Preview asks you to create a signature first, and it offers three ways to do it.

The trackpad method lets you draw your signature with a finger and press any key when you are done. The camera method lets you sign on a blank white sheet of paper and hold it up to your Mac's camera; Preview captures it and turns it into a reusable signature. The iPhone or iPad method puts a signing pad on your nearby device, where you sign with a finger or an Apple Pencil, and the signature appears on your Mac. Try all three if you can and keep the one that looks most like your real signature.

Once the signature is saved, click the Sign button again and pick it from the list. It drops onto the page as a movable box: drag it over the signature line and resize it with the corner handles until it fits. You can create more than one signature, which is handy when a document needs both a full signature and initials. After you save and reopen the file, the signature becomes part of the page and can no longer be selected, which is exactly what you want before sending it on.

One shortcut is worth knowing: you can sign a PDF attachment directly in Mail without saving it first. Open the attachment, click the Markup button, add your signature the same way, and send the reply from there. That is how to sign a PDF on Mac when the document arrives by email and you never want to leave your inbox.

How to sign a PDF on an iPhone

Use Markup, the built-in annotation tool in the Files and Mail apps. Open the PDF in Files, tap the Markup icon (the pen tip), tap the plus button, and choose Add Signature. Sign your name with your finger, tap Done, then drag the signature onto the line and resize it with the dots around its outline. Your iPhone saves the signature automatically, so the next document only needs a tap to place it again.

Apple's own support guide describes the same flow for forms: open the document, tap the Markup button, tap Add Signature, sign with your finger, tap Done, and drag the signature where it belongs. The guide also notes that you can create multiple signatures for different documents, and that AutoFill can complete the form fields from your Contacts card before you sign.

The same tool works in more places than Files. In Mail, open the attachment, tap Markup, and sign from there. In Notes, you can scan a paper form with the camera, then open Markup and add a signature to the scan. In Apple Books, open the PDF, tap the Markup icon, and follow the same plus-button path. If a PDF refuses to open in Markup at all, save it to the Files app first and reopen it from there.

Markup adds a visual signature to the page. That is fine for everyday paperwork, but it does not record an audit trail or verify your identity the way a dedicated e-signature platform does. For a lease, a freelance agreement, or a consent form, use a platform signer instead, or at least keep the email thread that shows the signed file was sent and accepted.

How to sign a PDF on Windows

Use Adobe Acrobat Reader's Fill & Sign tool, which is free with an Adobe account. Open the PDF in Acrobat Reader, choose Tools, then Fill & Sign, and click the Sign icon in the toolbar. If this is your first signature, a panel offers the three standard choices: type your name and pick a signature-style font, draw your signature with a mouse or stylus, or browse for an image of your handwritten signature. Click Apply, then click where the signature belongs on the page.

Adobe's own Fill & Sign page confirms the tool is free with an account and works on desktop, in any browser, and on any device. Your signature is saved for reuse on future documents, and a PDF signed this way can be opened by anyone with a PDF viewer; the recipient needs no Adobe account. The same page draws a useful line: Fill & Sign is for signing documents yourself, while Request E-Signature is for sending documents to other people and collecting their signatures, with routing, tracking, and multiple signers.

If you would rather not install anything, the Acrobat online signer at acrobat.com works in the browser instead. Upload the PDF, use the form-filler tools for any fields, then use the e-sign tools to place your signature or initials anywhere in the file. Sign in to save the file to Adobe cloud storage and download the finished form. A seven-day Acrobat Pro trial is also offered on the same page, but you do not need it just to sign your own copy.

How to sign a PDF online free

Use a free web signer when you are on a borrowed computer or a Chromebook with no signing app installed. You can sign PDF online free with no account at all, which is the whole point of the method below. SignWell's free signer is built for exactly this case: it signs one-off documents with no software to install and no account required. Upload the PDF, Word document, or image, drag your signature, initials, and dates onto the page in the browser, then download the finished file. SignWell deletes your document and data automatically after you download it, and it never asks for a credit card for the free tier.

The free limits are generous for occasional use: up to three files per document, up to 25 MB each, and Word, PDF, PNG, JPG, TIFF, and GIF files are all accepted. The files are combined into a single PDF for signing, and the signed result downloads as one PDF. One restriction matters: your files must not be password-protected, or the signer cannot open them. If your file is locked, password-protect a PDF is the wrong direction; you need the unlocked original, or you need to remove the protection first.

DocuSign's free route works differently: sign up for a free trial, choose New, then Sign a Document, upload the PDF, and drag your electronic signature from the left panel onto the page. It is a full e-signature platform, so the flow includes account creation and a trial clock, where SignWell's does not. Pick SignWell for a single quick signature with no account, and a platform such as DocuSign when you will be sending documents for other people to sign and want the routing and tracking.

Before uploading a sensitive contract to any free web tool, check two things. First, confirm the tool deletes your file after you download it, as SignWell does. Second, confirm the download is the signed PDF itself and not a link that forces the recipient to create an account. Both of these are stated on SignWell's own page; if a tool does not state them, do not upload anything you would not want stored.

Where exactly should the signature go?

The signature goes on the line marked for it, usually at the bottom of the last page, above the printed name and date. If the document has no line, place it in the empty space directly above your printed name, aligned with the left margin, and keep it inside the page margins. A signature that overlaps the body text or runs off the page edge looks careless and can be cropped by the recipient's printer.

Size matters more than most people expect. A signature box around 60 mm wide and 25 mm tall fits a standard A4 or US Letter signature line; a smaller 50 by 20 mm box suits a short line or an initials box. The table below gives the exact size in points and as a share of the page, computed from the standard conversion of 72 points per inch and 25.4 mm per inch.

If you want those numbers worked out for your own file before you sign, the free signature placement planner takes the file name, page count, signature page, and page size, and returns the box position in millimetres, points, and percent, with a visual preview and a fit check against the page. It is a planner only: it never uploads, signs, or saves your file.

What if someone else needs to sign it?

Then you need a sending flow, not just a signing flow. In DocuSign, you upload the document, enter the names and email addresses of the people who need to sign, compose a message, and send it; DocuSign routes the document to each signer and lets you watch the signing status as it moves. SignWell's free signer works the other way around for one-off files: you sign first, then send the finished PDF yourself, and recipients who only need to review and sign through a SignWell link do not need an account.

Whichever route you take, send the file as a PDF and keep the signed copy that comes back. If the document arrives as several separate files, merge PDF files into one document before sending it, so nobody signs the wrong page. If it arrives with pages you do not need, split a PDF first and send only the pages that require a signature.

Mistakes that make a signed PDF useless

The most common mistake is signing the wrong copy. If you sign a draft and the sender later sends a revised version, your signature belongs to the old file and means nothing on the new one. Confirm you have the final version before you sign, and sign the file the sender actually sent, not a printout you scanned back in.

The second mistake is signing before filling in the rest of the form. Fill in every field first, then sign last; a signature added early can be pushed off the page when a long answer wraps onto another line. The third mistake is forgetting the date. Most signature blocks include a date line for a reason: the date proves when the agreement was signed, and an undated signature invites an argument later.

The fourth mistake is uploading a password-protected file to a web signer and wondering why it fails. Free signers cannot open a locked file, so either get the unlocked original or remove the protection before uploading. And the fifth mistake is treating a Markup scribble as a legally tracked signature. A drawn signature in Preview or Markup is a picture on a page; it carries no audit trail. For anything that could end up in a dispute, use a platform signer that records who signed, when, and from where, and keep that record with the file.

PDFs are the default format for paperwork because they look the same everywhere, which is why they dominate the document statistics in our roundup of PDF statistics for 2026. Signing them on screen, rather than on paper, is simply the same habit applied to the last step.

Sources

• DocuSign, "How to electronically sign a document" (updated April 30, 2026) — ESIGN Act and UETA compliance, the sign-a-PDF steps, and the electronic versus digital signature distinction: https://www.docusign.com/en-au/learn/how-electronically-sign-document
• SignWell, "Sign Documents Online for Free" — free one-off signer with no account, three files up to 25 MB each, automatic deletion after download, and the audit trail: https://www.signwell.com/sign-documents-online/
• Adobe Acrobat, "Fillable PDF form creator: Create and sign forms" — Fill & Sign is free with an account, type, draw, or upload a signature, and Fill & Sign versus Request E-Signature: https://www.adobe.com/acrobat/features/sign-fillable-pdf-forms.html
• Apple Support, "Fill out forms, sign documents, and create signatures on iPhone" — Markup Add Signature steps and multiple saved signatures: https://support.apple.com/guide/iphone/fill-forms-sign-documents-create-signatures-iph1d3607e5c/ios
• MacMost, "Signing PDF Documents On Your Mac" — Preview trackpad, camera, and iPhone signature methods, placement, and signing directly in Mail: https://macmost.com/signing-pdf-documents-on-your-mac.html
• SmallPDF, "How to Sign a PDF on iPhone for Free" — iPhone Markup steps in Files and Photos and the saved-signature reuse: https://smallpdf.com/blog/how-to-sign-a-pdf-on-iphone

Frequently asked questions

Is it legal to sign a PDF electronically?

Yes, in the United States an electronic signature on a PDF is legal and binding for nearly every business transaction under the ESIGN Act and UETA, as long as both parties agree to sign electronically and the signer clearly intends to sign. A platform signer that records an audit trail gives you the proof if the signature is ever questioned.

Can I sign a PDF without Adobe?

Yes. On a Mac, Preview's built-in Sign tool does it for free with no Adobe software at all. On an iPhone, Markup in the Files app does the same. On Windows without Adobe, use a free web signer such as SignWell in any browser, which needs no account and no download.

How do I sign a PDF on my phone?

On an iPhone, open the PDF in Files, tap Markup, tap the plus button, choose Add Signature, draw your name with your finger, and drag it onto the line. On Android, the Adobe Acrobat Reader app's Fill & Sign tool follows the same pattern: open the PDF, choose Fill & Sign, create a signature by typing, drawing, or uploading, and place it on the page.

Is there a totally free way to sign a PDF online?

Yes. SignWell's free signer lets you upload a PDF, add a signature in the browser, and download the signed file with no account and no credit card, and it deletes your file automatically after download. The free tier accepts up to three files of 25 MB each. Adobe's Fill & Sign is also free, but it requires a free Adobe account.

What is the difference between an electronic signature and a digital signature?

An electronic signature is any symbol or data attached to a document with the intent to sign, most often an image of your handwritten signature. A digital signature is a type of electronic signature that uses encryption to verify the signer's identity. Standard electronic signatures are enough for everyday paperwork; digital signatures add identity proof for transactions that need it.