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How to sign a PDF on an iPhone

Checked 20 September 2026

An iPhone is the best device for signing a PDF, because you sign with a finger on glass rather than dragging a mouse. Apple builds this in: you can fill out and sign PDF forms on iPhone, and Markup lets you create signatures and reuse them.

Here is Apple's route first, then where a browser tool helps.

Step by step

  1. 1Save the PDF to FilesFrom Mail or Messages, tap the attachment, then share it to the Files app so you have a copy to work on.
  2. 2Open it and fill in any fieldsTap a field and type. AutoFill can offer details saved on your iPhone.
  3. 3Open MarkupTap the Markup button, then the add button, then Add Signature.
  4. 4Sign with your fingerSign on the line. Tap Clear and sign again if you are not happy. Signatures you create are saved for reuse in supported apps.
  5. 5Place, resize and shareDrag the signature into position and pinch to resize, then share the finished document back by email.

What Markup can't do

  • Markup draws on top: nothing is flattened, so your signature stays a movable annotation.
  • Typing onto a flat form means adding a text box by hand for every answer.
  • No tick or date fields, and no way to produce a Word version.
  • Signatures are tied to your iPhone rather than available in a browser on any device.

Finish it here instead

Type onto the page, tick the boxes, add the date and a signature you can reuse, then save a flattened PDF. It runs in this browser — your file is not uploaded.

or drop a file here · nothing is uploaded

Questions

Can I sign a PDF on an iPhone without an app?
Yes. Markup is built into iOS, and PDFpad works in Safari on the same phone if you need typed fields, ticks, dates or a flattened result.
Why does my signature look better on a phone?
Because you draw it with a finger at something close to writing speed. A mouse or trackpad produces the wobble everyone recognises.

Sources

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