I will be expected to comply with all relevant rules of procedural, evidentiary, and substantive law. Learn what an acknowledgement receipt is and how to create one for your business (with a template and two examples).In addition, the specified documentation of costs and expenses set out in each Addendum will also be required to be submitted to support payment of an invoice. They can use the envelope the server sent them. Paternity. Parent Survey on the Acknowledgement of Paternity (AOP). Please sign the enclosed acknowledgment of service form in the presence of a notary and return the form to me in the enclosed self-addressed, stamped envelope.