If you would like to enable Digital Signatures on a PDF that is going to be passed to different users through a LiveCycle ES Process, here are a few short guidelines for you.
On the form itself:
The form must be a PDF
Keep in mind that the DigSigs are applied to the PDF so the hidden submit field on your PDF form must submit a PDF and not an XDP or you will just be submitting the data of the PDF
In the process design:
The required input field to the process must be of type Document Form
Change the render service to the sample render service (and the associated variables should be corrected)
In the advanced setting be sure that the “call the render service only once” is checked – if not, the form will be refreshed and signatures removed each time the form is displayed in Workspace
If you would like a sample of a PDF Form and a Process including a Digital Signature, feel free to download this LCA (LiveCycle Archive for Adobe LiveCycle ES) https://share.adobe.com/adc/document.do?docid=b71a87c5-f6a8-11dc-8d05-e593509263b8