Your Mac Already Has the PDF Signature Tool You Need

That PDF sitting in your Downloads folder does not require an Adobe subscription or an upload to an unfamiliar document website. Every Mac includes Preview, and the app can create, store, position, and resize a handwritten signature directly on a PDF.

The feature is easy to miss because Preview opens documents with most of its editing controls hidden. Once the Markup toolbar is visible, signing a form takes only a short sequence of clicks. You can write the signature on a trackpad, capture one from paper with the Mac’s camera, or draw it on a nearby iPhone or iPad.

Open the PDF in Preview

Double-click the PDF in Finder. If another application opens it, close the file, Control-click it in Finder, and choose Open With > Preview. With the document open, click the Show Markup Toolbar button if the toolbar is not already on screen.

Click the Sign button in that toolbar. Preview will display any signatures already saved on the Mac. If the list is empty—or you need a different version—choose the option to create a new signature.

Choose one of three ways to write it

Use the trackpad

Select Trackpad, click when Preview prompts you, then write your name with a finger. Press any key when you are finished and select Done. On a Mac with a Force Touch trackpad, firmer pressure can produce a heavier, darker line. The trackpad method is quick, although it may take a few attempts before the result resembles your normal signature.

Capture a signature with the camera

For a more natural result, sign your name with dark ink on plain white paper. Choose Camera, hold the paper in front of the built-in camera, and align the signature with the blue guide shown in Preview. When the captured version looks clean, click Done. Good lighting and a bold pen help the camera separate the writing from the page.

Draw on an iPhone or iPad

Choose Select Device and pick a nearby iPhone or iPad. Write with a finger, or use an Apple Pencil on a compatible iPad, then tap Done. This option depends on Apple’s Continuity requirements, so the devices need to be configured to work together. It is often the easiest method when the trackpad feels awkward.

Place the signature and finish the form

After creating the signature, select it from the Sign menu. Preview inserts it as a movable object on the current page. Drag it over the document’s signature line, then use the corner handles to adjust its size. The signature remains editable while you work, so zoom in and check that it is aligned before saving.

Preview can also handle the rest of many forms. Click an existing form field and type. If the PDF does not contain interactive fields, open the form-filling tools and add a text box over the blank area. This is useful for dates, printed names, addresses, and short responses.

Choose File > Save when everything is in place. It is wise to save a copy under a new filename before editing an important original. Open the saved version once more and inspect every page, especially if the PDF contains several signature or initial fields.

You can reply with the signed file from Mail

When a PDF arrives as an Apple Mail attachment, double-click it to open it in Preview, complete the form, and save the changes. Preview can then create a reply to the sender or a new message with the edited PDF attached. That avoids downloading the file, signing it, and manually finding it again for the reply.

Know where the saved signature goes

Preview keeps captured signatures available for reuse. If iCloud Drive is enabled, Apple says those signatures can also appear on your other Macs. That is convenient on a personal setup, but it deserves attention on a shared computer.

To remove one, open the Sign menu, move the pointer over the saved signature, and click the X. Apple notes that deleting it removes the signature from Mac apps that use Markup and, when iCloud Drive is active, from other Macs connected through iCloud Drive.

A visible signature is not identity verification

Preview places a handwritten signature on the page, which is enough for many routine forms. It does not create an independent identity check, a certificate-backed digital signature, or a detailed signing audit trail. If a bank, employer, government office, or contract platform requires a particular signing service, follow that process instead of assuming a Preview signature will qualify.

For ordinary PDFs, though, the built-in route is fast, private, and already installed. Open the document in Preview, reveal Markup, choose how to capture your signature, place it carefully, and save a checked copy.

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