iPhones have surprisingly capable built-in PDF signing tools — most people don't know they exist. Here are the four best ways to sign a PDF on iOS.
Method 1: Files App (iOS 15+)
- 1Open the Files app and find your PDF
- 2Tap the PDF to open it
- 3Tap the pen icon in the top-right (Markup)
- 4Tap the + button → Signature
- 5Draw your signature with your finger
- 6Tap Done, then drag the signature into position
Method 2: Mail App
If you received the PDF via email, tap and hold the attachment → Markup. This opens the same Markup interface without saving to Files first.
Method 3: Safari (Browser-Based)
Open Signpdf in Safari on your iPhone. The PDF editor works on mobile — tap to upload, draw your signature with your finger, and download the signed PDF directly to your Photos or Files.
The browser-based option works on any iPhone with iOS 14+ — no app download required.
Method 4: Adobe Acrobat Reader (Free tier)
Adobe's free iOS app lets you sign PDFs, though some features are paywalled. For basic signing it works, but you'll need to create an Adobe account.
Which Is Best?
- Quickest (no setup): Files app or Mail
- Most control over placement: browser-based (Signpdf)
- Need to sign a lot of documents: Adobe Acrobat Reader
Works great on iPhone — try it in Safari right now.
Sign a PDF →