How to sign a PDF on a Mac

Signing in Preview, step by step

Double-click the PDF. If it opens in a browser or Acrobat instead, right-click it and choose Open With > Preview. If the Markup toolbar is hidden, click the Show Markup Toolbar button (a pen tip in a circle) at the top of the window, then click the Sign button, which looks like a signature on a line.

The first time, you will be asked to create a signature. After that, your saved signatures appear in the list and you just click one. It drops onto the page; drag it to the signature line and pull the corner handles to resize it. Save with Command-S, or use File > Export as PDF to keep the original untouched.

Three ways to create your signature in Preview

Apple's Preview guide offers three methods. Each gives a slightly different result.

• Trackpad: click Trackpad, click the text prompt, sign with one finger on the trackpad, press any key, then click Done. A Force Touch trackpad picks up pressure for a more natural line.
• Camera: click Camera, sign on plain white paper with a dark pen, hold it up to the camera so the signature sits on the blue line, and click Done when it appears. This usually gives the most authentic result.
• iPhone or iPad: click Select Device, sign on the phone or iPad screen with a finger or Apple Pencil, and tap Done. Both devices need to meet Apple's Continuity requirements.

Filling in the rest of the form

If the PDF has form fields, click into them and type. Preview fills standard PDF forms. If the boxes are just lines on the page with no fields, click the Text button in the Markup toolbar, type, and drag the text box into position. For the date, add a text box beside your signature.

Preview also keeps your signatures in iCloud, so the same signature is available on your other Apple devices signed in to the same account.

Signing it yourself versus getting it signed

Preview stamps an image of your signature on the file. That is what most people need when a document has been sent to them. But if you are a freelancer sending a contract out, or a landlord sending a lease, Preview cannot help you collect the other person's signature in a way you could rely on later. Emailing a PDF and asking them to sign in Preview gets back a file with no record of who signed, when, or whether the clauses were edited first.

Sign PDF does that part. Upload the PDF or Pages file in Safari or Chrome and we place the signature, initials and date boxes and assign each to a signer by reading the labels around them. Add names and emails and send. Each signer confirms a six-digit code from their email and signs in the browser. The finished PDF carries a certificate of completion, is sealed with a digital signature and DigiCert timestamp, and opens in Preview like any other file. Plans are $5 or $10 a month.