Allow users to upload "printed and signed" copy on behalf of external party

Currently, if a external party (client, prospect etc) is signing a document, they have the ability to Print and Sign which then gives them the ability to upload it back. Most never go back through that process and just email it over after its either signed through a “wet signature” or through whatever program they use internally. So our process in Docusign basically skips and we have to complete it through a separate manual process. If we had the ability to “upload signed copy” on their behalf/for them we could continue the process including all the triggers that things are complete, pulling the document in etc. This is not limited to triggering from Salesforce, but in our case, it would greatly improve usage in Salesforce rather than having 50%+ starting in Salesforce and then ending in the same ol manual way, skipping all the benefits of using the Salesforce integration in the first place (status updates, automatic attachment etc).