Receiving a PDF contract, invoice, or form that requires your signature no longer means printing, signing, scanning, and emailing the document back. macOS includes a surprisingly capable PDF editor built directly into the Preview application. Using Preview, you can add text annotations, highlight important clauses, draw shapes, and most importantly, insert a legally valid electronic signature—all without installing Adobe Acrobat or any third-party software.
Why Preview Is Sufficient for Most PDF Tasks
While Adobe Acrobat Pro offers advanced features like form field creation and document encryption, the vast majority of everyday PDF interactions involve simple tasks: reading, annotating, and signing. Apple’s Preview handles all of these natively. Your signature is captured once and stored securely in your Mac’s keychain, making it instantly available across all Apple devices linked to your iCloud account.
Opening a PDF in Preview
By default, macOS opens PDF files in Preview unless you have changed your default application.
- Locate the PDF file in Finder.
- Double-click the file. It will open in Preview.
- If it opens in a different application, right-click the file, hover over Open With, and select Preview.
Highlighting and Annotating Text
Preview provides a complete set of annotation tools accessible from the Markup Toolbar.
- With the PDF open in Preview, click the Markup button in the toolbar (it looks like a pen tip inside a circle). This reveals the Markup Toolbar.
- To highlight text, click the Highlight button (the marker icon) in the Markup Toolbar. Select your preferred colour from the dropdown arrow next to it.
- Click and drag your cursor across the text you want to highlight.
- To add a text note, click the Text button (the “T” icon). A text box will appear on the page. Type your annotation and drag the box to the desired location.
- To draw a shape such as a rectangle or an arrow, click the Shapes button and select the shape you need. Drag it onto the document and resize it by pulling the blue handles.
Creating Your Digital Signature
The first time you sign a PDF, you will need to create your signature. Preview offers three methods.
- In the Markup Toolbar, click the Sign button (the signature icon).
- Click Create Signature.
- You will be presented with three capture methods:
- Trackpad: Click the trackpad tab, click the “Click Here to Begin” area, and write your signature with your finger on the trackpad. Press any key when finished.
- Camera: Write your signature on a plain white piece of paper. Hold the paper up to your Mac’s camera, aligning it with the guide line on screen. Preview will automatically detect and capture the signature.
- iPhone or iPad: If you have a nearby Apple device, click the iPhone/iPad tab. Your device will display a signing canvas where you can use your finger or an Apple Pencil for a more precise result.
- Click Done to save the signature.
Your signature is now permanently saved and can be reused on any future PDF document.
Inserting Your Signature into a PDF
Applying your saved signature to a document takes only a few clicks.
- Open the PDF in Preview and activate the Markup Toolbar.
- Click the Sign button. Your saved signature(s) will appear in the dropdown menu.
- Click the signature you wish to use. It will appear on the current page as a movable, resizable object.
- Drag it to the signature field on the document.
- Use the corner handles to resize the signature so it fits naturally within the provided line.
- Click anywhere outside the signature to finalise its placement.
- Save the document by pressing Command + S.
Removing Annotations and Signatures
If you make a mistake, every annotation and signature added through Preview is fully editable until you close the document. Simply click the annotation to select it, then press the Delete key to remove it. If you have already saved and closed the file, reopen it, select the annotation, and delete it. Preview preserves annotation layers as separate objects, so your original PDF content is never permanently altered.