An Acknowledgment of Paternity (AOP) is a legal document that allows parents who aren't married to establish legal paternity. An acknowledgment is one of the most common types of notarial acts, but it often confuses Notaries.Here are 5 steps to performing an acknowledgment. An acknowledgment copy will be returned to the filer, along with an acknowledgment letter, detailing what was indexed into the Filing Officer's indexing system. The Acknowledgment Letter will serve as proof that the non-resident attorney has satisfied the required fee. Required Documentation. A complete subdivision application will consist of the documents and content listed below. Per a new state law, Tarrant Appraisal District is sending homeowners letters asking them to confirm their homestead exemption.