After creating a custom entity in CRM, you can share its documents (i.e. Text, Office, Image, PDF, etc.) with other users to get them digitally signed. In case the document (being shared) is other than PDF, then SigningHub will convert it into PDF format before sharing it with the configured signer(s).
The process of sharing the documents of a custom entity is exactly the same as of any other CRM entity, i.e. navigate the custom entity, then create a new object inside the custom entity, then browse its "Notes" tab and attach your document(s), and then share through SigningHub. For details, see share documents of a CRM entity for signing. The recipient user(s)/ signer(s) will be notified through email(s) by SigningHub (upon their turn) to sign the document.
The shared documents can be seen with the "In-Progress" status, inside the "Check Status" screen.