How to sign a PDF on iPhone — with Markup, and without it
To sign a PDF on an iPhone, open it in Files or Mail, tap Markup, then Add Signature and draw with your finger. When Markup is not offered — a Gmail preview, a link in Chrome — open Sign PDF in Safari instead.
Your iPhone can already sign a PDF, and for most documents that built-in route is the right answer — offline, and nothing to install. The reason people go looking anyway is that the pencil icon is not always there: a contract opened from a link, a preview inside the Gmail app, a file Chrome decided to display rather than hand over. Here is the Apple way first, then the browser way for when the Apple way does not show up.
How do I add a signature on my iPhone?
Open the PDF in Files or in Mail, tap the Markup icon, tap the plus button, and choose Add Signature. Draw your name with a finger, tap Done, then drag the signature onto the line and resize it from a corner. No app, no account, no connection.
It is genuinely good, and iOS keeps the signature you drew, so the second document takes about four taps. One tip that costs nothing: turn the phone sideways before you sign. The drawing strip is the width of the screen, and landscape gives your hand roughly twice the run-up, which is the difference between your signature and a seismograph reading.
How do I add a signature to a PDF on my phone without Markup?
When Markup is not offered, open Sign PDF in Safari and sign in the page instead. It behaves the same on iPhone, iPad and Android, because it is a web page rather than an app, and the document is read and rewritten on the phone itself.
Open the tool in Safari
Open Sign PDF. It loads as an ordinary web page — there is nothing to install and no account to make.
Choose the PDF
Tap the upload area and pick the file from Files, or from wherever you saved it. Every page is rendered on your phone first, so a long document takes a moment before the signature pad appears.
Sign with your finger
Draw on the pad in black or blue ink. Or switch to Type and enter your name to have it set in a script face.
Confirm it
Tap Use signature. It is trimmed to its own edges, so the blank space around your name does not become blank space around the image.
Place it and apply
Drag the signature onto the line, resize it from a corner handle, then tap Apply signature. Safari saves the signed copy into Downloads in the Files app.
How do I insert a handwritten signature in a PDF?
Draw it with a finger, which is the one part of this a phone does better than a laptop. The pad and the placement box both switch off the browser's own touch gestures, so a finger dragged across either one draws or moves rather than scrolling the page out from under you.
The eight resize handles look like small dots but answer to a tap area nearly three times their width, which is what makes them catchable with a fingertip rather than a mouse pointer. Resizing from a corner stays locked to the signature's own proportions, so it cannot be stretched into a caricature of itself.
Placement is handed to the PDF as a fraction of the page rather than as pixels on your screen, and we measured what that buys you. The same signature, dropped at the same relative spot on a 390-pixel-wide phone stage and on a 760-pixel-wide desktop one, landed in an identical place in the finished PDF — the same distance in from the left edge, the same distance up from the bottom, the same width and height, matching to two decimal points. A small screen costs you precision while you are aiming. It does not cost you accuracy in the result.
How can I sign a PDF that was emailed to me?
In Apple Mail, tap the attachment and the Markup icon is right there. The Gmail and Outlook apps render their own preview and do not offer it. Tap the share icon, choose Save to Files, and sign the saved copy by either route.
Sending it back is the step people forget. A signature applied in Markup is written into the file when you tap Done, so the copy in Files is the signed one. A signature applied in Safari arrives as a separate new file with _signed on the end of the name. Attach that copy, not the original you opened out of the email.
How do I insert a digital signature in a PDF file?
Neither route makes one. Markup and this tool both add a picture of your signature to the page. A digital signature is a cryptographic certificate bound to the document's exact bytes, which proves who signed and reveals any change made afterwards.
The distinction matters more than it sounds, and it is worth being blunt because nobody selling a signing app will be. A drawn signature carries no identity check — anyone who can open the file can draw the same name — and no record of when it was signed. For a delivery note, an internal approval or a school form that is completely adequate, and always has been. For an employment contract, or anything a court might end up reading, use a qualified e-signature provider. Drawn, typed, digital: three kinds of PDF signature lays out which is which.
What the signed file comes out like
- The page is not turned into a picture. We stamped a signature onto a test document and read the result back with a different library than the one that wrote it: the text underneath was still there and still selectable, and exactly one image had been added, on exactly one page.
- One signature, one page, per pass. A contract needing initials on three pages is three rounds of sign, download, re-open — worth knowing before you start rather than at page two.
- Typing instead of drawing asks for Segoe Script first, which is a Windows font your iPhone does not have. On iOS the request falls through to Bradley Hand, which Apple does ship, so the same typed name looks different on a phone than it does on a PC. The preview shows you what you are getting, so look at it.
- Your original is untouched. What you get back is a new copy ending in _signed.
All of it happens in the Safari tab you already have open: the PDF is read, drawn on and saved on your phone, and neither the document nor your signature is uploaded or kept anywhere afterwards, because nothing is transmitted anywhere. How to sign a PDF covers the desktop flow and the placement details in full, and if the document has real form fields to complete as well, Fill PDF Forms handles those first.
