Fill out and sign PDF forms in Preview on Mac
Some PDFs are forms you can fill out and then print or send. (PDF forms that aren’t editable won’t allow you to select or enter text.) If a form requires a signature, you can add your signature to the PDF.
Fill out a PDF form
In the Preview app
on your Mac, open the PDF form.Click a field in the form, then type your text.
If you save the form (by choosing File > Export), you can close it, open it later and continue to fill it out.
Create and use signatures
To sign PDFs, you can capture your signature using your trackpad, the built-in camera on your Mac, or your iPhone or iPad.
In the Preview app
on your Mac, click the Show Markup Toolbar button 
(if the Markup toolbar isn’t showing), then click the Sign button 
.Follow the onscreen instructions to create and save your signature.
Create a signature using your trackpad: Click Trackpad, click the text as prompted, sign your name on the trackpad using your finger, press any key, then click Done. If you don’t like the results, click Clear, then try again.
If your Mac has a Force Touch trackpad, you can press your finger more firmly on the trackpad to sign with a heavier, darker line.
Create a signature using your computer’s built-in camera: Click Camera. Hold your signature (on white paper) facing the camera so that your signature is level with the blue line in the window. When your signature appears in the window, click Done. If you don’t like the results, click Clear, then try again.
Create a signature using your iPhone or iPad: Click Select Device to choose a device (if more than one is available). On your device, use your finger or Apple Pencil (on iPad) to sign your name, then click Done. If you don’t like the results, click Clear, then try again.
Click the Sign button
, then click the signature to add it to your PDF.Choose the signature you want to use, drag it to where you want it, then use the handles to adjust the size.
If you use iCloud Drive, your signatures are available on your other Mac computers that have iCloud Drive turned on.
Delete a saved signature
In the Preview app
on your Mac, click the Show Markup Toolbar button (if the Markup toolbar isn’t showing).Click the Sign button
, position the pointer over the signature, then click the X to the right.
The signature is deleted from all apps that use Markup on your Mac computer. If you have iCloud Drive turned on, the signature is also deleted from your other Mac computers that use iCloud Drive.