How to sign a PDF on iPhone

You can sign a document on your iPhone without a printer or a scanner: open the PDF, add your signature and send the file back. Here are three ways — the built-in Files app, Notes for a paper document, and a dedicated app if you sign often or the document has many pages.

One thing first: all three put an image of your handwritten signature on the document — the same as signing a printout and scanning it. That is an electronic signature in the everyday sense, but not a certificate-based digital signature. If you have been asked for the latter, read that guide first.

Method 1. The Files app

Use this when the document arrived as a PDF — by email, in a messenger or as a download.

1. Save the PDF to Files: open it in Mail or your messenger, tap Share → Save to Files.
2. Open it in Files and tap the Markup button — the pen icon.
3. Tap “+” in the toolbar and choose Add Signature. Sign with your finger and tap Done.
4. Drag the signature onto the line and resize it from a corner.
5. Tap Done — the changes are saved to the same file. Send it with Share.

Your iPhone remembers the signature, so you will not have to draw it again. The limits: the signature can only be drawn with a finger, and on a long contract you have to place it page by page.

Method 2. A paper document — scan it in Notes

If you have the document on paper but need to return a file, turn it into a PDF first:

1. In Notes, create a note, tap the paperclip or camera icon and choose Scan Documents.
2. Point the camera at the page — the iPhone finds the edges and straightens it. Scan every page and tap Save.
3. Open the scan, tap Share → Markup and add your signature as in method 1.

You can save the scan to Files as a PDF and treat it like any other document from there.

Method 3. A signing app

The built-in tools are fine for a one-off. If you sign often — invoices, contracts, forms — a dedicated app is quicker. In Signature: sign documents it works like this:

1. Open a PDF from Files or a photo of a document from your library.
2. Pick a saved signature or initials — draw them with a finger or capture them from paper: the white background turns transparent, leaving your real signature.
3. Drag it into place and adjust the size. If every page needs it, copy it to all pages at once or only to the ones you pick — say, 1 and 3–5.
4. Save the result as PDF, JPG or PNG — to Files or Photos.

No account is needed, and documents are processed on your phone. The app is free to download; signing documents comes with PRO.

Make your signature look natural

• Sign big. A signature drawn small on glass looks jagged. Use the whole pad, then shrink it on the page.
• Try paper. A pen on paper looks more like you than a finger on a screen. Photograph it and use that.
• Do not stretch it. Resize from a corner so the proportions stay right.
• Set up initials too. Many contracts ask you to initial every page and sign in full at the end.

If the document is in Word

Convert a .docx to PDF first: open it in Word or Pages on your phone and export it as PDF, then sign the PDF with any of the methods above. A signed PDF is also harder to change by accident and looks the same on every device.

In short

• Sign a PDF right in Files: Markup → “+” → Add Signature.
• For a paper document, scan it in Notes first, then sign.
• For frequent or multi-page documents, an app is easier: a signature from paper, copying to every page, saving as PDF, JPG or PNG.
• A signature image is not a certificate-based digital signature.