How to Sign a PDF on Mac (Preview, Trackpad, or iPhone)

Every Mac can sign a PDF for free — no Adobe subscription, no printing and scanning. Preview captures your signature once, from your trackpad, your Mac's camera, or your iPhone, then keeps it on file so signing the next document takes three clicks.

Find the Sign button

1. Open the PDF in Preview (double-click it — Preview is the default PDF app).
2. Click the Markup button in the toolbar — the pen-tip icon. A second toolbar appears.
3. Click the Sign button (the squiggle) and choose Create Signature.

Three capture methods appear as tabs — pick whichever suits your hardware. This flow is identical on macOS 13 Ventura, 14 Sonoma, and 15 Sequoia.

Capture your signature

• Trackpad — click Click Here to Begin, sign with your fingertip on the trackpad, press any key when finished, then click Done. Slow, deliberate strokes come out best; a stylus-like capacitive pen on the trackpad works even better.
• Camera — sign your name in black ink on white paper, then hold the paper up to the Mac's camera so the signature rests on the blue line. Preview traces it into a clean vector with a transparent background — usually the best-looking result, and the closest to your real signature.
• iPhone or iPad — click Select Device, and your signature pad opens on the nearby device; sign with your finger or Apple Pencil and tap Done. The device needs to be signed into the same Apple ID with Bluetooth and Wi-Fi on. The Pencil-on-iPad route gives the most natural line of all.

Signatures are saved in the Sign menu for reuse — capture once, sign forever. Hover over one in the list and click the ✕ to delete it if it comes out wobbly, then recapture.

Place it on the page

1. Scroll to the signature line and click the Sign button again.
2. Click your saved signature — it drops onto the page.
3. Drag it onto the line, and resize it with the corner handles; the proportions stay locked so it never stretches oddly.
4. Need a date or printed name too? Use the Text tool in the same Markup toolbar to add a text box beside it.
5. Save (Cmd + S), or File → Duplicate first if you want to keep an unsigned copy.

What this is — and isn't

Preview places an image of your signature in the PDF: legally fine for the everyday lease, permission slip, and contract-by-email, and universally readable by any PDF app. It is not a cryptographic digital signature of the kind some government and enterprise workflows require — if a form demands a certificate-based signature, you'll know, because it will say so and Preview won't offer it. One practical tip on top: if the recipient needs the form fields typed too, do the typing first — Preview's form filling and signing live in the same Markup toolbar and coexist happily in one pass.

Two workflow habits worth adopting. First, keep a clean unsigned master of any form you sign repeatedly, and sign duplicates (File → Duplicate) — Preview auto-saves, so signing the only copy quietly bakes the signature into it. Second, remember the saved signatures stay on this Mac and appear in the Sign menu for every future PDF, so anyone who shares your user account can stamp your signature too. On a shared machine, hover each signature in the Sign menu and delete it with the ✕ once the paperwork is done.

Next stop for the same PDF

Signed forms often need to be emailed — and scanned PDFs can be enormous. Before you attach it, see how to compress a PDF without extra apps.