How to Sign a PDF on iPhone
An iPhone signs PDFs with no app at all. The gap that is left is the contract that arrives on paper and is not a PDF yet.
The free way: Apple Markup
If the document is already a PDF, you do not need to install anything.
- Open the PDF in Files, Mail or Books.
- Tap the Markup button. It is the pen tip icon.
- Tap the plus button and choose Signature.
- Draw your signature with a finger or an Apple Pencil. Signatures you have saved before are offered here, so you only draw it once.
- Drag it onto the line, resize it, and save. The signature is written into the file.
That is genuinely enough for most day to day paperwork, and it costs nothing. Use it.
The gap: the contract is on paper
Markup needs a PDF. When the document arrives as paper, the usual route is scan in one app, export, open in another, sign, export again. Paperlane closes that loop by putting the signing step next to the scan.
- Scan the pages. Free, and the same VisionKit capture as everywhere else.
- Open the document and swipe to the page with the signature line. The signing tool works on the page you are actually looking at, not always the first one.
- Choose Markup and sign. A drawing canvas opens over the page. Draw the signature, or add initials and notes wherever they are needed.
- Confirm. The drawing is flattened into that page, so it survives every viewer, every print and every re export.
- Optionally set a password, then share. Both are in the same menu as the signing tool.
Markup and sign and password protection are part of Paperlane Pro, the one time $4.99 purchase. Scanning the contract, reading it, reordering its pages and sharing it are free.
What a drawn signature is, and is not
It is an image of your handwriting placed on the page and burned into the file. For a rental form, a school letter, a delivery note, a consent slip or an internal approval, that is exactly what is being asked for, and it has been for as long as fax machines existed.
It is not a qualified electronic signature. There is no certificate tied to your identity, no cryptographic seal on the document, no trusted timestamp, and no audit trail recording who opened and signed what. Nothing stops the image from being copied out of the file. If a counterparty requires a qualified or advanced electronic signature, or wants an audit record, use a service built for that purpose. No scanner app of any price replaces one.
One technical detail worth knowing
Flattening means the signed page is rebuilt as an image with the drawing baked in. The page looks identical and keeps its position in the document, and every other page is left untouched. The trade is that the signed page loses the invisible text layer it had, so search will no longer find words on that one page. If searching the signed page matters more than a permanent mark, keep the unsigned original as a duplicate before you sign, which the library does in one tap.
Get Paperlane
Free on the App Store, iOS 17.0 or later. Rated 5.0 out of 5 from 1 rating.