Here’s a relatively easy way to add a digital signature to any document on a Mac. This method works with any PDF document. Keep in mind that if you have a Word document you can save it as a PDF and then apply this method.
The first step is to create your digital signature. To do this launch the Preview program.
Next, select Tools->Annotate->Signature->Manage Signatures->Create Signature.
You now have an option of using the Track Pad or the Camera. I used the camera. Scribble your signature on a piece of white paper and hold it up to the camera and take its picture. Your signature is now stored in Preview. Yeah!
Open up any PDF you want. Select Tools->Annotate->Signature and click on your signature. That will place it in the PDF document and you can move it to the proper location. That is it. Of course, don’t forget to save the file.