Oh, you bet you can! If you’re wondering how to edit a PDF on a Mac to add a signature, use the Preview app. Open the PDF in Preview, click the markup icon, then select the sign tool. You can add your signature by using your trackpad or camera and put it wherever you wish in the PDF. It is a convenient and fast method of signing forms and documents without printing. It is among the simplest means to edit a PDF on a Mac without the use of other applications.