Mac users have it easier than most when it comes to signing PDFs. macOS ships with a built-in tool that handles signatures well. But there are also browser-based options that work without any software at all — useful when you're on someone else's machine or want to keep things simple.
Method 1: Preview (built-in, always free)
Preview is macOS's default PDF viewer and it has a surprisingly capable signature feature. Here's how to use it:
- Open your PDF in Preview. If it opens in another app, right-click the file → Open With → Preview.
- Click the markup toolbar icon — the pencil icon on the far right of the toolbar. If the toolbar isn't visible, go to View → Show Markup Toolbar.
- Click the signature button (it looks like a cursive S or a pen nib).
- Choose how to create your signature:
- Trackpad: Click "Click Here to Begin," sign with your finger on the trackpad, then press any key to finish.
- Camera: Sign your name on white paper, hold it up to the webcam, and Preview captures it automatically.
- iPhone/iPad: Select this option to draw on a connected Apple device.
- Click your saved signature to insert it into the document.
- Drag it into position and resize using the corner handles.
- Press ⌘S to save. Preview flattens the signature into the PDF.
Method 2: Browser-based signing (no software needed)
If you prefer not to deal with Preview, or you want to upload a cleaner signature image, a browser-based tool works entirely within Safari or Chrome — no installation required.
- Go to quickpdfsign.com in your browser
- Drop your PDF onto the upload area
- Draw your signature with your trackpad, type your name, or upload a PNG
- Click to place it on the page
- Download the signed PDF
The PDF is processed entirely in your browser — nothing is uploaded to a server. The downloaded file is a standard, flattened PDF.
Method 3: Quick Look with markup
macOS Ventura and later versions let you annotate PDFs directly from Quick Look (the Space bar preview). Select the PDF in Finder, press Space to open Quick Look, then click the markup icon in the top right. The signature tool is available there too, using the same signatures saved in Preview.
This method is faster to open but has the same capabilities as Preview — use whichever is more convenient.
What about Adobe Acrobat on Mac?
Adobe Acrobat Reader (the free version) lets you fill and sign PDFs, but it's a large app (500MB+) and adds very little for basic signing compared to Preview. Acrobat Pro adds features like form creation and certified signatures, but it costs $24.99/month — not worth it if you're just signing occasionally.
Does Preview produce a legally valid signature?
Yes. Under the E-SIGN Act (US) and eIDAS (EU), electronic signatures are legally binding regardless of the software used to create them. A Preview-generated signature has the same legal standing as one created with a paid service.
For documents requiring identity verification or a certified audit trail (certain financial or legal filings), a specialized service may be required — but for the vast majority of everyday documents, Preview is sufficient.
Which method to use
- Signing regularly: Preview is the best choice — fast, built-in, and saves your signature
- Need to upload a high-quality signature image: Use the browser tool with the Upload option
- On someone else's Mac without your Apple ID: Browser-based tool at quickpdfsign.com
- Need multiple signatures or initials in many places: Preview handles this well — you can insert the same saved signature multiple times