How to Sign a PDF on iPhone (Built-In, 10 Seconds)
The short answer
Sign a PDF on an iPhone with the built-in Files app — open the PDF, tap the pencil icon, add a signature, and done. No downloads, no accounts, and the signature looks like your actual handwriting if you draw it with your finger. It’s genuinely one of the smoothest things iPhones do.
Sign a PDF with the Files app
- Open the PDF in the Files app (download it there first, or AirDrop it).
- Tap the pencil icon in the top-right corner to open markup.
- Tap the plus (+) button → Signature.
- If it’s your first time, draw your signature with your finger (or let iPhone use your saved one).
- Drag it into place, resize if needed, tap Done → save.
Your signature is saved on the phone after the first drawing — the next document takes about ten seconds total.
Better than signing on paper? Mostly yes
For almost everything — contracts, permission slips, rental agreements — a finger-drawn signature on an iPhone is accepted fine. The honest caveat: it’s a drawn signature, not an audited electronic signature. If the document requires verified identity (real estate closing, government filings), the bank or agency will specify their own signing service — use theirs.
The honest part
Two things people trip on:
- “Where’s the save button?” After tapping Done, the app may return to the viewer without an obvious save. The signature is already in the file — close it and check the gallery in Files; the signed copy is what you see now. If it doesn’t stick, use the Share sheet → Save to Files explicitly.
- Signature position. Drag it by the center; it snaps roughly into place. It won’t align to printed signature lines perfectly — close enough is genuinely close enough for most recipients.
And a workflow tip: if the document arrived in Mail or a website, you don’t need to transfer it anywhere — open the attachment in Quick Look and tap the markup icon (the pencil in the top-right of the attachment view) directly. Same signature tools, zero extra steps.