How to resize a signature on a PDF on iPhone

You dropped your signature onto the PDF and it came in the size of a headline — sprawling across the sender’s address block instead of sitting neatly on the line. Or the opposite: a tiny scribble hovering above a line built for something four times bigger.

This is a two-second fix once you know where the handles are. Here’s the free way first.

The free fix: resize it in iOS Markup

If the signature is still an annotation — meaning you placed it in Markup and haven’t exported, printed or flattened the file — you can resize it as many times as you like:

Open the PDF in Files, Mail or Photos and tap the Markup icon (the pen tip). If you’re not in Markup, taps do nothing but scroll the page.
Tap the signature once. A thin outline appears around it with small blue dots at the corners and edges.
Drag a corner dot to make it bigger or smaller. Corners keep the shape; the side dots stretch it, which makes handwriting look squashed — stick to corners.
Or pinch directly on the signature with two fingers. Same result, easier for small adjustments.
Tap Done, then save or share.

That’s the whole answer for most people, and it costs nothing. What Markup won’t do is remember the size — the next document starts from scratch, and if you’re signing several a week you’ll be re-dragging the same handle forever.

If tapping it does nothing: the signature isn’t an annotation any more. That happens when the file was exported flat, printed to PDF, or came back to you as a scan. At that point the signature is part of the page image and no tool can resize it — see what flattening actually does. The fix is to go back to the original unsigned PDF and sign it again.

It landed in the wrong place, not just the wrong size

Same selection, different gesture:

To move it, press and drag from the middle of the signature, not from a dot. Dragging a dot resizes; dragging the centre moves.
Zoom in first. Pinch the page out to about 200–300% before you position anything. At full-page zoom a signature can look perfectly seated and still be floating three millimetres above the rule when the recipient opens it on a laptop.
Nudge with small drags. iOS has no arrow-key nudge, so zoom is your precision tool — the further in you are, the finer each drag becomes.
Check the other pages. If a document asks for initials throughout, size them once and match the rest — mismatched sizes across pages are the clearest tell that a document was signed on a phone in a hurry. Adding initials to every page covers that flow properly.

What size is actually right?

There’s no rule in any spec, but there is a look that reads as signed rather than edited:

Match the printed text height. The main body of your signature should be roughly the cap height of the type around it, with the flourishes and descenders allowed to break out. If it’s twice the height of the printed name below it, it’s too big.
Fill about two-thirds of the line. Not the whole width — signature lines are drawn long deliberately. Wall-to-wall ink looks stretched.
Sit on the rule. The baseline of your name should touch the printed line, with descenders crossing below it, exactly like handwriting on paper.
Keep the proportions. Never drag a side handle to fit a narrow space. A horizontally squashed signature is instantly recognisable as a pasted image.
Same size as the date beside it. A signature and a giant date next to it read as two separate events — size the date to the line too.

Why it comes in oversized in the first place

Almost always because of the image behind it. A signature drawn edge-to-edge on a big canvas — or saved as a photo of paper with lots of white space around it — carries all that empty margin with it, so the visible ink looks small inside a box that’s actually huge. Cropping tight to the ink before you place it fixes the problem at the source; a signature saved as a transparent PNG, trimmed to the strokes, drops in at a sensible size and without a white rectangle covering the text underneath.

Doing it in Signed

Signed is built around the repeat case — the same signature, sized the same way, on document after document:

Import the PDF from Mail, Files, Photos or any app’s share sheet.
Place your saved signature where it belongs, then drag to fit the line.
Add the date, initials, printed name, text or a checkmark if the form asks for them — each placed and sized the same way.
Zoom in to check it sits on the rule, on every page.
Export a flattened PDF and send it back.

Because your signature lives in a library rather than being redrawn each time, the second document takes seconds — and it looks identical to the first. The document itself never leaves your iPhone: there’s no upload step in the middle, which matters when the PDF is a lease with your salary on it.

Before you send it

Open the finished file one more time in a plain viewer — Files, or the preview in your mail app — and look at it at full page size, the way the recipient will. Signature on the line, sized like handwriting, date matching, nothing overlapping the printed text. Thirty seconds of checking beats a “can you re-send that?” reply the next morning.

Signed is a tool for signing and filling PDFs, not a source of legal advice. If the document matters — a lease, a contract, anything with money attached — read what you’re signing and check what the recipient actually requires.