If you would not like to use the section ootb Signature Capture field on your PDF Document there are a few different strategies you could use. If the user already has the signature file, you can create a custom activity and add the step, "Call pyAttachAsPDF" or "Code-Pega-List.AttachToWork" to attach your image to the pdf in your assignment, or you could create your PDF as a section and add the Capture Signature field to it in Pega and create HTML that references the section and displays the signature below as shown in the PDF below. Next you would create an activity that Converts the HTML to a PDF and attaches the generated signature to your PDF which will be attached to your case. On the section that you created you will need a generate button with an action that refreshes the case on a click and runs the activity that you created. I hope that this helps.