How to Sign a PDF on iPhone for Free
Your iPhone can already sign PDFs: Apple's Markup tool draws your signature onto the document right from Files, Mail or Photos. For a document that is just for you, that is all you need. If someone else is going to receive the signature (a contract, a quote, a permission slip), you want an electronic signature with an audit trail: just as easy, but with proof of who signed, when, and that the document was not changed afterward.
In 30 seconds
- Apple Markup (in Files or Mail) draws your signature onto the PDF: free, no app, works offline. Fine for documents that are just for you.
- If someone else receives the document, use an electronic signature with an audit trail: date, time, the document's hash and, if another person signs, their email, IP address and time.
- Both are valid electronic signatures (ESIGN in the US, eIDAS in Europe); the difference is the proof you have if someone disputes it.
Option 1: Apple Markup (Files or Mail)
- Open the PDF in the Files app, or tap the attachment in Mail.
- Tap the Markup icon (the pen tip, top right).
- Tap "+" and then "Signature." The first time, draw your signature with your finger; your iPhone saves it for next time.
- Drag the signature into place on the document and resize it with the corners.
- Tap "Done" and share the PDF by email or WhatsApp, or save it to Files.
It is free, installs nothing and works offline. What it does is draw: the PDF comes out with your signature on top, the same as if you had pasted it in as an image. It does not record who signed, when or from where, and anyone who has your signed PDF can copy the signature image onto another document.
Option 2: an e-signature with an audit trail (also free)
- Open Sign for free in Safari, no account needed, and upload the PDF from Files or a photo of the paper.
- Choose "Just me," tap "Add my signature" and sign with your finger. Tap the spot on the document where it goes.
- Tap "Finish": download the signed PDF or send it to someone.
The PDF comes out with an audit trail on the last page: date and time, the document's SHA-256 hash and an electronic seal, so any later change is detected. And if someone else has to sign, you choose "Other people": they get a link, sign on their phone, and it comes back to you signed with their email, IP address and time.
Which one should I use?
| Situation | Apple Markup | E-signature with audit trail |
|---|---|---|
| A form of your own that no one will dispute | Yes | Yes |
| A contract, quote or agreement with someone else | Better not: no proof of who or when | Yes: it is on record |
| You need someone else to sign | They have to do it on their own iPhone and send it back | You send a link and it comes back signed |
| Several people or several copies | One at a time, by hand | Up to 20 people per request |
| Offline | Yes | No |
Is a signature made on an iPhone legally valid?
Yes, with either option. In the United States, the federal ESIGN Act defines an electronic signature as any electronic "symbol or process" adopted with the intent to sign, and in Europe the eIDAS regulation says a signature cannot be denied legal effect just because it is electronic. The difference is the proof: if someone denies they signed, with Markup all you have is the drawing; with the audit trail you have the email or phone number it was sent to, the IP address, the date and time, and the document's hash. We explain it in Are electronic signatures valid in the United States?
Tips
- Sign slowly and big: it shrinks to fit the box on its own.
- If the PDF has several pages, go to the page you are signing before you tap.
- If you only have the document on paper, take a photo of it: MultiDocs turns it into a PDF.
- Always keep a copy of the signed document.
FAQs
Can I sign a PDF on my iPhone without installing an app?
Yes. Markup comes built into iOS, and MultiDocs runs in Safari with nothing to download and no account to create.
Is a Markup signature a valid electronic signature?
Yes: it is an electronic symbol adopted with the intent to sign. What it lacks is an audit trail: there is no record of who placed it or when, so it is harder to defend if someone disputes it.
How do I get someone else to sign from their iPhone?
In MultiDocs choose "Other people," type their name and their email or phone number, and they get a link. They sign with their finger on their iPhone, no account needed, and you receive the signed PDF with the audit trail.
Can I sign a Word document on my iPhone?
Save it as a PDF first (in Word or in Pages: Export as PDF), then sign it.
Does MultiDocs keep my document?
When you sign on your own, it is processed on your own iPhone. It is only stored, encrypted, when you send it to someone else to sign, and it is deleted afterward.
Official sources
- Apple: use Markup to sign documents on iPhone
- Cornell LII: 15 U.S.C. § 7006 (definitions: electronic signature, consumer)
- EUR-Lex: Regulation (EU) 910/2014 (eIDAS)
We checked each source on 5 November 2026. If you spot an out-of-date figure, write to us at info@multidocs.es.