How to Sign a PDF on iPhone
Your iPhone can already sign a PDF for free — most people just don't know where the button is. Here's the built-in Markup method step by step, the cases where it gets awkward, and what to do when the document you need to sign is still a piece of paper.
Method 1: Sign a PDF in the Files app (built-in, free)
If the PDF is already on your phone — downloaded from Safari, saved from a message, sitting in iCloud Drive — iOS Markup is all you need. No app, no account, nothing uploaded.
- Open the Files app and tap the PDF to open it.
- Tap the Markup button — the pen-tip icon at the top right. (On some iOS versions it lives inside the share button instead.)
- Tap the + button in the Markup toolbar and choose Signature. On iOS 17 and later this reads "Add or Remove Signature."
- Sign on the line with your finger, then tap Done. Turning the phone sideways gives you a much bigger line to work with.
- The signature lands on the page. Drag it into place, use the blue handles to resize it, and tap Done to save the signed PDF.
iOS remembers the signature. Next time, + → Signature shows the one you saved — tap it and it drops onto the page. You can keep more than one (a full signature and a set of initials, say) and delete any of them from the same menu.
Forms too
Since iOS 17, Files detects fillable fields in many PDFs and offers AutoFill — tap a field and type. Combined with a saved signature, that handles most one-page forms without any third-party app.
Method 2: Sign a PDF attachment in Mail
You don't have to save the attachment first. Mail has the same Markup toolbar built in.
- Open the email and tap the PDF attachment to view it full-screen.
- Tap the Markup icon (pen tip) at the top right — or, back in the message, long-press the attachment and choose Markup and Reply.
- Tap + → Signature, pick your saved signature or draw a new one, and drag it into place.
- Tap Done. Mail offers to attach the signed copy to a reply — choose Reply or Reply All and it's on its way.
The same trick works in Messages, Safari (share → Markup) and Notes, because they all share one Markup toolbar and one list of saved signatures.
Where the built-in method falls short
Markup is genuinely good for the "someone emailed me a PDF, I need to sign it and send it back" case. Four situations where it stops being enough:
- The document is on paper. Markup needs a PDF to draw on. A lease or consent form handed to you across a desk has to be scanned first — Notes can do it (Scan Documents), but now you're juggling two apps, and the crop-and-straighten step comes before you ever see a signature line.
- The signature is an annotation, not part of the page. Markup stores it in a separate layer. Reopen the file and the signature is still movable and deletable — by you, or by whoever you send it to. A few PDF viewers and upload portals flatten or ignore annotations, and the signature quietly disappears.
- Multi-page documents. Initials on every page of a 12-page contract means twelve rounds of + → Signature → drag → resize.
- Finger signatures look like finger signatures. The drawing box is small, and without an Apple Pencil the result is often shakier than your real signature. You can redo it, but only from scratch — Markup has no way to touch up a saved signature.
Method 3: Sign a scanned document with Scaniva
If your starting point is paper, or you want the signature baked into the page rather than floating on top of it, this is the flow in Scaniva (version 4.5.0 or later):
- Get the document into Scaniva: scan it with the camera, import it from Photos or Files, or use Open in Scaniva from the Mail or Files share sheet.
- Open the document and tap Sign.
- The first time, tap Add Signature, draw with your finger or Apple Pencil, and tap Use Signature. Scaniva keeps it under Saved Signatures — up to five, so a full signature and your initials can both be ready.
- Tap a saved signature to drop it on the page. Drag to move, pinch to resize. Repeat on any other page that needs one.
- Tap Export → PDF. The signature is flattened into the page — it's part of the document now, not a removable layer.
From there the PDF goes anywhere the share sheet goes: Mail, Files, AirDrop, WhatsApp. If it's the kind of document that shouldn't be forwarded casually, export it with a password instead — see how to password-protect a PDF on iPhone.
What it costs
Signing, password protection and watermarks are part of Scaniva's Full Version — $12.99 one time, no subscription, no account. The free version scans and exports PDFs with a small footer on each page. Everything, including the signature you draw, stays on your iPhone; there is no cloud component to trust.
Which method should you use?
- Emailed PDF, one signature, done: Markup in Mail. Fastest, free, nothing to install.
- Downloaded form with fields: Markup in Files, with AutoFill for the boxes.
- Paper document: Scaniva — scan, sign and export in one app instead of bouncing between Notes and Files.
- Signature must stay put, many pages, or reused initials: Scaniva, because the signature is flattened on export and saved signatures are one tap away.
Sign it where you scanned it
Scaniva scans, signs, password-protects and exports — on your iPhone, without a subscription. Free to try, $12.99 once for the Full Version.
Download on the App StoreFAQ
Is a signature drawn on my iPhone legally valid?
In the US, the ESIGN Act and UETA give electronic signatures the same standing as ink for most agreements, and the EU's eIDAS regulation recognizes a drawn signature as a "simple electronic signature." That covers leases, consent forms, offer letters and most everyday contracts. Wills, some real-estate deeds and anything that requires notarization or a certificate-based "qualified" signature are exceptions. This is not legal advice; when in doubt, ask the party requesting the signature.
Can I sign a PDF on iPhone for free?
Yes. Markup in the Files and Mail apps costs nothing and needs no download. Scaniva's free version scans and exports PDFs; signing is part of the $12.99 one-time Full Version.
How do I add a signature to a photo of a document?
Convert the photo to a PDF first (share → Print → pinch outward, or long-press the image in Files → Create PDF), then sign it with Markup. Or import the photo into Scaniva, which crops and straightens it, tap Sign, and export. The photo-to-PDF guide covers the conversion step in detail.
Can the recipient remove my signature?
A Markup signature is stored as an annotation layer, so anyone with a PDF editor can move or delete it. Scaniva flattens the signature into the page image on export, so removing it would mean editing the picture itself.
Does Apple Pencil make a difference?
Yes. Both Markup and Scaniva accept Apple Pencil on iPad, and the strokes are noticeably smoother than a fingertip. On iPhone it's finger only — turn the phone sideways, sign large, then shrink the signature on the page.