Creating a stateless form to have a supervisor sign an employee filled out record

Creating a stateless form to have a supervisor sign an employee filled out record

My goal is to have an employee fill out a request form, sign it, and when submitted an email will be sent to their supervisor (one of the fields the employee enters is supervisor email), with a record template filled with the record information, and a link to a stateless form where they can sign and date. The signature and date would then be updated in the original record.

I am able to create everything above, except the stateless form, as it seems the signature field is not included in stateless forms for whatever reason. What is an alternative to this? A different approach would be to just have a normal form with supervisor signature and date, not a stateless form, but how can I connect the record created in this form to the original record the employee created?