Custom Built App Integration for Dynamic PDF

Hi all,

I am attempting to implement a very specific use case that I’d hope/assume is possible:

Background Info:
We have developed an internal tool for a client that allows users to create daily work records. These daily work records are dynamic, obviously, due to the record containing the work performed for that day. Currently, the end of each day, the users download the pdf, email it to their customers, and have them download and digitally sign however they can, and resend it back. We are already generating a pdf with the data for that day, so once the record is submitted for the day, that document is static.

The Feature:
We want to take this static pdf, and add a signature spot at the bottom of the page for the customer to retrieve an email with the docusign signature request, rather than a simple email with an attached document. The clear pathway I see that is probably the easiest implementation would be creating a blank template with a signature field on it, and when we send the email, we combine the blank template with the generated pdf. 

Do any of you have an idea of how to implement something in this manner or have a better solution? This is my first time utilzing the Docusign APIs so forgive my ignorance. 

Thanks