When you receive a digital contract or a sensitive tax form via email, printing it out, physically signing it with a pen, scanning it back into the computer, and emailing it back is incredibly tedious and degrades the document quality. To instantly inject a perfect, legally binding, vector-based signature directly into the PDF without ever touching a piece of paper, you must use the native macOS Preview application.
Creating Your Digital Signature
Before you can sign a document, you must capture your physical signature and store it in the encrypted macOS Keychain.
- Double-click any PDF file to open it in the Preview application.
- Click the Show Markup Toolbar button (the small pencil icon near the top-right corner).
- In the new toolbar that drops down, click the Sign icon (it looks like a small cursive signature).
- Click Create Signature.
macOS will present you with three completely different methods to capture your signature:
- Trackpad: Click the “Trackpad” tab. Click the text that says “Click Here to Begin”. Using your physical finger (or a capacitive stylus), physically write your signature directly onto your Mac’s glass trackpad. The trackpad acts as a high-resolution digitizer. Press any key on the keyboard when you are finished, and click “Done”.
- Camera: If you hate signing with your finger, write your signature on a clean, blank piece of white paper using a thick black pen. Click the “Camera” tab and hold the paper up to your Mac’s webcam. The neural engine will instantly detect the high-contrast ink, strip away the white paper, and digitize the signature perfectly.
- iPhone/iPad: If you own an iPhone or iPad, click this tab. Your mobile device will instantly wake up and display a blank canvas, allowing you to use your finger or an Apple Pencil to draw the signature, which is instantly beamed back to your Mac via Bluetooth.
Injecting the Signature into a PDF
Once your signature is securely stored in the system, signing documents takes exactly two seconds.
- Open the target PDF in Preview and expose the Markup Toolbar.
- Click the Sign icon. A drop-down menu will appear displaying all your saved signatures.
- Click your desired signature.
The signature will instantly drop into the absolute center of the PDF page. It is a mathematically perfect vector graphic, meaning it has a completely transparent background. You can click and drag it to the specific “Sign Here” line, and you can drag the blue corner handles to resize it perfectly to fit the document.