How to sign, annotate, and edit a PDF on a Mac computer using Preview

You can edit a PDF on your Mac with Preview, an app that's built-in to your computer from the start. You can use this program ...

How to digitally sign a PDF when you don't have access to a printer and scanner

You can digitally sign a PDF in several different ways, including Adobe Acrobat, Apple's Preview app, and mobile apps, among other options.