Sign a PDF on a Mac

Sign a PDF in Preview

Preview is on every Mac and MacBook, and it signs well. Open the PDF, show the Markup toolbar, click the Sign button and create a signature. There are three ways to capture it. Draw on the trackpad with a finger and press a key when you are done. Sign a piece of white paper and hold it up to the camera, which gives the most natural result. Or pick your iPhone or iPad from the list and sign on its screen.

Preview stores the signature, so every later document takes seconds. Click it in the Sign menu, drag it onto the line, resize it from the corners and save. The same signature appears in Markup in Mail, so an attachment can be signed and sent back without leaving the message.

Sign a PDF on a Mac in the browser

Sign PDF opens in Safari, Chrome or Firefox. Drag the PDF from Finder onto the page, then draw a signature with the trackpad, type your name, or upload a scan of your signature. Place it on each page that needs it, and download.

The file and the signature stay in the tab, and the signature is not saved anywhere, which suits a shared Mac or a work machine. The tool reopens the signed PDF and checks every mark is visible before the download appears.

Initials on every page

Leases and loan agreements often want initials at the foot of every page and a full signature at the end. In Preview, create a second signature that is just your initials and place it page by page. In Sign PDF, add the initials as a second mark and place it on each page.

Keep the size and position consistent from page to page. It looks deliberate, and anyone checking the document finds the initials where they expect them.

Sign it last

Fill the form, join any extra pages and compress the file before you sign. A drawn signature is page content, so it survives those steps, but signing last means you check its position once, on the finished document. Fill a PDF form on a Mac covers the fields, and merge PDFs on a Mac covers adding pages.

If the signed file is too big for an email or an upload form, compress it on the Mac to the exact size the form asks for.

Certificate signatures on a Mac

Preview and Sign PDF both place a drawn signature, which is what most forms and contracts ask for. A tender or an official filing can ask for a certificate signature instead, which locks the file to your identity. Adobe Acrobat Reader for Mac is free and signs with a certificate. Digital vs electronic signature explains the difference, and sign a PDF on your phone covers the same job on an iPhone, iPad and Android. The signing hub lists every signing guide.