Good luck to us, Adobe support was not even able to adequately explain this to me.
What I know - Adobe Sign uses Send For Signature which allows anybody you specify as an email recipient to sign or initial. You have to create the fields (as far as I can tell each and every time). I would love to be able to add these to a form template and not have the end user signing able to edit the form. You can specify multiple signers by adding an email address to the appropriate Signature or initial field and it will carry over to all over them. For example, "Signer 1" "Signer 2" The signer can either type their name and uses a standard template for the initial or signature, or depending upon their device use their finger or a stylus. They click their way through the document authorizing each field to add their respective initial or signature and then finalize it when done. The form is then sent to the next signer in the order specified or finalized/flattened and emailed as a secure PDF to all parties if complete.
Digital Signatures is what I have been trying to learn about and Adobe has been no help. If you do not click Send For Signature Tool/Prepare Form or through the More button on the right sidebar of the Prepare Form tool "Convert to Adobe Sign Form" then one of the Form Fields available to add is "Digital Signature." All I am trying to find out is should I choose this method which apparently uses a digital certificate or digital ID for the signing party, how can you add initials from the signing party to the same form where needed?
To me, the Send For SIgnature/Adobe Sign process seems the better solution if only I could have those initial and signature fields added to my form template and not have the signing parties able to change the text fields and check boxes while they are reviewing and signing. Oh and get this, there is apparently a 10MB (yes Megabyte) limit to documents being used with Adobe Sign as an individual Acrobat Pro DC monthly subscriber even though I have a 20GB cloud storage in DC. If you want to be able to send out larger files for e-signing you need an enterprise account. Thanks Adobe! NOT
Hope this helps somewhat or at least stimulates a dialogue on these topics. Thanks for posting.