Guide · Updated · By Buğra Sözeri
How to Sign a PDF (Free, on Any Device)
Most devices can already sign a PDF without paid software. This guide covers the general process, then links to device-specific walkthroughs for iPhone, Android, Mac and Windows.
Step by step
- Open the PDF in a tool that supports annotations. On a Mac use Preview, on iPhone or iPad use the Files app, and on Windows or Android use the free Adobe Acrobat Reader app. Any of these can add a signature.
- Find the signature option. In Preview it is the Sign button in the Markup toolbar. In the Files app it is Markup, then the + button, then Add Signature. In Acrobat Reader it is Fill & Sign.
- Create your signature. Draw with a mouse, trackpad or finger, type your name, or use an image of your handwritten signature, depending on what the app offers.
- Place and resize it. Drag the signature onto the signature line and resize it so it fits the space. Add the date or your printed name with a text field if the document asks for it.
- Save a copy. Save or export the signed file. Keep the original unsigned version too, in case you need to correct something.
Signing it yourself vs. collecting signatures
Adding your own signature to a PDF is a quick edit you can do in any of the apps above. Getting another person to sign is different: you need to send the file, track whether it was signed and keep a record of who signed and when.
For the second case, an e-signature service that records an audit trail is usually the better fit. eSignSimple lets you send documents for signature with an audit trail from a PDF or Word document; the Free plan covers 3 documents a month.
A browser-based option
If you would rather not install anything, eSignSimple's free Sign PDF tool is included with a free account (sign up with Google) and runs in your browser. You upload the PDF (it is encrypted at rest), draw or type a signature, add the date, and download the signed copy with an audit trail; it counts as one of your monthly documents.
Device-specific guides
See our step-by-step guides for signing a PDF on iPhone, on Android, on Mac and on Windows, and for signing a PDF without printing it.
Built-in app, browser tool or e-signature service: which should you use?
Built-in apps (Preview, Files, Acrobat Reader) are best when you sign your own copy and send it back. They are free and offline, but they leave no record beyond the picture on the page. A browser tool such as our Sign PDF tool suits borrowed computers and phones where you cannot install anything. An e-signature service is the right choice when you need somebody else's signature: it sends the link, reminds the signer, and keeps an audit trail of who opened and signed the document and when.
If the PDF has form fields to complete as well, fill them first and sign last; our guide on how to fill out a PDF covers flat and fillable forms.
What are the most common mistakes when signing a PDF?
Signing an old version is the classic one: always check the file name and date against the latest email. The second is missing a spot, because leases and contracts often ask for initials on every page as well as a signature at the end. The third is saving over the original and then needing to correct a typo. And finally, people forget to flatten or export: some apps keep the signature as an editable annotation, so exporting a fresh PDF before sending makes it harder for anyone to move it around.
And if you meant the sign-off at the bottom of your emails rather than a document, that lives in your mail settings; see how to add a signature in Outlook. If you are wondering whether any of this counts legally, read are electronic signatures legally binding for the short answer by region.
Why did my signature disappear or move after I sent the PDF?
Most free apps add your signature as an annotation: a layer that sits on top of the page rather than part of the page itself. Good PDF viewers show annotations, but some email previews, older office printers and lightweight phone viewers ignore or misplace them. The result is the call every freelancer dreads: "there's no signature on this". The signature was there in your app; the recipient's viewer simply did not draw it.
The fix is to flatten before you send. In Preview, use File > Export as PDF to a new file; in most other apps, a Print to PDF (or Microsoft Print to PDF on Windows) produces a copy where the signature is baked into the page. Then open that new file in a different viewer, such as your browser, and check every signed page. If the signature shows up there, it will show up for the other side too.
How do I sign a PDF with several signature spots and initials on every page?
Leases, loan paperwork and longer contracts often ask for initials at the foot of every page plus a full signature and date at the end. Take a 12-page residential lease: that is 12 sets of initials, one signature, one printed name and one date, and missing a single initial is enough for a landlord to send the whole thing back. Before you start, scroll through and count the spots, then work from page one to the end so you do not skip one.
Create your initials as a second saved signature in the same app, so you can drop them in with two clicks per page instead of drawing them twelve times. Our guide on how to add initials to a PDF covers each app. If you are the one sending a long document out, place an initials field on every page in an e-signature service instead: the signer is taken from field to field and cannot finish until every required one is done.
A two-minute check before you send a signed PDF back
Open the exact file you are about to attach, not the copy still open in your editor. Check that every signature, initial and date is on the right line and readable at normal zoom. Confirm the date format matches the country the document comes from: 04/11/2026 is 11 April in London and 4 November in New York. Rename the file so it is obvious which copy is final, for example "Lease-2026-signed.pdf", and keep the unsigned original in the same folder.
Watch the file size as well. A scanned 20-page PDF can easily pass the 25 MB attachment limit that Gmail and many other mail services enforce, in which case the mail app quietly swaps the attachment for a cloud link the recipient may not be able to open. If that happens, sign a digital original rather than a scan, or compress the scan before signing.
What happens if the sender uses a signing link instead of an attachment?
Then you do not need any of the tools above. You click the link in the email, read the document in your browser, tap each highlighted field and sign by drawing or typing. There is nothing to download, no app to install and no account to create. When the last person has signed, everyone receives the completed PDF by email, usually with a certificate page at the end that lists who signed, when, and from which IP address.
That certificate is what turns a picture of a signature into evidence. With eSignSimple, the final PDF also carries a SHA-256 fingerprint, so either side can drop the file onto the verify page years later and confirm it has not been altered. If you regularly need other people's signatures, how to send a document for signature walks through the sender's side.
Our take
Most people overthink this. If the only signature on the page is yours, the free app already on your device is fine, and paying for software to sign your own PDF is money wasted. The moment another person has to sign, the question changes from "how do I put ink on this" to "how will I prove they agreed". That is where a pasted image falls short and a signing link with an audit trail earns its keep. Decide which of the two situations you are in before you pick a tool.
Sources and further reading
Frequently asked questions
Is it free to sign a PDF?
Yes. Preview (Mac), the Files app (iPhone and iPad) and Adobe Acrobat Reader all let you add your own signature for free, as does eSignSimple's Sign PDF tool.
Is a signature added this way legally valid?
In many countries, including the US under the ESIGN Act and the EU under eIDAS, electronic signatures are generally valid for most everyday documents. Some documents have special requirements, so check if you are unsure.
Can I sign a scanned PDF?
Yes. A signature can be placed on any page, scanned or not, because it is added as a layer on top of the page.
Do I need to print and scan?
No. All of the methods above sign the file digitally, so there is no need to print it.
Which method gives the strongest evidence?
Sending the document through an e-signature service. It records emails, timestamps, IP addresses and a document fingerprint, which a signature pasted into a PDF cannot provide.
Can I sign a password-protected PDF?
If the password only restricts editing, most apps will refuse to add a signature until the restriction is lifted, and removing it without the owner's permission is not a good idea. Ask the sender for an unlocked copy or ask them to send it through a signing link instead.
Can I change a PDF after I have signed it?
Technically, many apps will let you, which is exactly why a signed PDF should be treated as final. If a term needs to change, correct the document and sign a new version rather than editing the signed one.
Does the date next to my signature have to be handwritten?
Almost never. A typed date in a text box is normal for electronic signing. Signing services usually fill the date automatically at the moment of signing, which is more reliable than a date typed by hand.
Get your next document signed today.
Start with 3 free documents a month. No card needed.