How to Sign PDF Documents Using the Preview App on macOS

When you receive a digital PDF contract or permission slip via email, you do not need to print it out, sign it with a pen, and scan it back into your computer. macOS includes a highly advanced digital signature tool built directly into the default Preview application. Preview allows you to create a perfect, transparent, digital vector copy of your actual handwritten signature using either your Mac’s trackpad or its built-in webcam.

How to Access the Signature Tool

The signature creation tools are located inside Preview’s markup menu.

1. Double-click the PDF contract to open it in Preview.
2. Click the Markup Toolbar icon in the top right corner (the circle with a pencil tip inside).
3. In the newly revealed toolbar, click the Sign icon. It looks like a small, cursive signature with a line underneath it.
4. Click Create Signature from the drop-down menu.

A popup window will appear offering you multiple ways to capture your signature: Trackpad, Camera, or iPhone.

Method 1: Signing with the Trackpad

If you have a MacBook or an external Magic Trackpad, you can use your finger (or a capacitive stylus) as a pen.

1. Click the Trackpad tab in the popup window.
2. Click the button labeled Click Here to Begin.
3. Your Mac’s trackpad now acts exactly like a drawing tablet. Use your finger to slowly sign your name on the trackpad. Note: The trackpad maps directly to the box on screen, so try to use the entire surface area.
4. If you make a mistake, press the Clear button and try again.
5. When you are satisfied, press any key on your keyboard to stop capturing, then click Done.

Method 2: Scanning with the Camera

If you find it too difficult to sign with your finger, you can use a real pen and paper.

1. Sign your name clearly on a piece of bright white, unlined paper using a thick black pen.
2. Click the Camera tab in the popup window.
3. Hold the piece of paper up to your Mac’s webcam. Ensure the signature rests perfectly on top of the blue guide line on the screen.
4. macOS will instantly scan the paper, detect the black ink, strip away the white background, and create a perfect transparent digital copy. Click Done.

Placing the Signature on the PDF

Once your signature is saved into the system, it will securely sync via iCloud to all your other Apple devices. To use it, simply click the Sign icon in the markup toolbar again. Your newly created signature will appear in the drop-down list. Click it once, and it will drop directly into the center of your PDF. You can then click and drag the signature to the correct line on the contract, and use the blue corner handles to shrink or enlarge it until it fits perfectly.