How to add a signature to a photo of a document on iPhone

The photo is already taken. It’s sitting in your camera roll — a page of a form, a permission slip, an agreement someone put in front of you — and now it needs your signature on it.

You can do this on your iPhone for free, and for a lot of people the built-in tools are the whole answer. But there’s one decision to make first, and almost nobody mentions it.

First: does the person receiving it need a PDF?

This is the thing that decides everything below.

If you sign the photo in Photos, what you get back is a photo — a JPEG or HEIC image with your signature drawn on it. That’s genuinely fine for a lot of everyday situations: a school form going back to a teacher by text, a delivery confirmation, anything informal.

But if someone asked for a signed document — a landlord, an HR team, a bank, an insurer — they usually mean a PDF. Image attachments get bounced back with “can you send this as a PDF?” more often than any other reason. It costs you nothing to get the format right the first time, so decide now.

Option 1: Markup in Photos (free, already on your phone)

If an image is acceptable, this is complete and you don’t need anything else:

Open the photo in Photos and tap Edit.
Tap the Markup icon (the pen tip) in the top row of tools.
Tap + in the bottom corner → Signature.
Draw your signature with your finger, or tap Add or Remove Signature to reuse one you saved before.
Drag it onto the line, resize with the blue handles, and tap Done → Done again to save.

That’s it. Your signature is on the page and the edited photo is in your camera roll. (Photos keeps the original, so Edit → Revert undoes it if you put the signature in the wrong place.)

The honest limits: you get an image back, not a PDF. A signature drawn with a finger on glass takes a few attempts to like. And if the form also wants a date and your initials, those are separate text boxes you add and nudge into position by hand, one at a time — the same fiddling that shows up when you write on a PDF on iPhone with your finger.

Option 2: still free — turn the photo into a PDF first

If the recipient wants a PDF, iOS will make one out of your photo without any app:

In Photos, select the photo → Share → Save to Files, and pick a folder.
Open the Files app, long-press the image, and choose Create PDF.
A PDF version appears alongside it. Open it, tap the Markup (pen) icon, and sign it exactly as above — + → Signature.

Same signature, same effort, correct file type. Worth the extra twenty seconds any time the document is going somewhere official.

One thing to check before you send it. A PDF made from a camera photo is still a camera photo inside — if the page came out crooked, shadowed, or with a corner of your table in shot, converting it doesn’t fix any of that, and grey keystoned pages are the second most common reason documents get sent back.

If the paper is still within reach, the better move is to capture it again properly: iOS has a real document scanner built into Notes and Files that de-skews the page, crops it, cleans the contrast, and hands you a straight PDF directly. It takes about thirty seconds and it’s free — signing a scanned document on iPhone walks through that route end to end. If the paper is long gone and the photo is all you have, carry on with what you’ve got; a legible photo signed properly beats a delay.

Option 3: a signature app (when the photo is one of many)

If documents arrive this way more than occasionally, the per-document fiddling is the thing worth removing:

Open Signed and import the photo straight from Photos — it converts the image to a PDF for you, so there’s no Files detour.
Tap where the signature goes. Your saved signature drops in at the right size.
Initials, your name and today’s date are one tap each — the date fills itself in.
Tap Finish for a flattened PDF, where the signature is merged into the page rather than floating on top of it as an annotation, and share it back. (If you’re not sure why that matters, flattening a signed PDF explains it.)

You build the signature once, properly: draw it large on a clean canvas, type your name in a real handwriting style, or let AI generate one from your name. Every photo after that is the same handful of taps. And if you just want to see what a decent version of your signature looks like before committing to anything, the free signature generator runs in your browser — no signup, nothing uploaded.

On privacy: photos of documents are exactly the things you’d rather not hand to a server — they’re often IDs, bank letters, forms with your address on them. Signed is local-first: the photo and the signature stay on your phone, with no cloud copy.

Which should you use?

An image is fine, and it’s a one-off → Markup in Photos. Free, done, no app needed.
They want a PDF → Files → Create PDF, then Markup. Still free, twenty seconds more.
The paper is still in front of you → scan it instead of photographing it. Straighter page, better result.
This keeps happening, or the form wants initials on every page → an app removes the repeat fiddling from the first document onward.
It’s a high-stakes document → the tool is the easy part. A signature placed on an image may not be everything that’s required, so check what’s actually accepted for that document type before you send it.

What gets a signed photo sent back

Wrong format. They asked for a document; you sent a picture. Convert it.
An unreadable page. Shadow across the text, or the page shot at an angle.
A cropped edge. Signatures and dates near the margin get cut off — check all four corners.
Missing the date or initials. Forms almost always want more than the signature.
Several photos sent as several images. If the document has multiple pages, send one PDF with the pages in order.