The process server must fill out and sign the proof of service form, which shows how, when, and where the papers were served, and who received them. An affidavit of service, also sometimes called a proof of service affidavit, is a type of affidavit that relates to legal documents that are filed with a court.Serving papers on another person is an official handing over of documents. An affidavit for service is a legal document confirming the delivery of court papers to a party involved in a legal proceeding. An affidavit is a written statement, sworn to be true, that can be used as evidence in legal proceedings. A "Proof of Service" is a one-page document that must be attached at the back of every document filed in bankruptcy court. Proof of service is a document that functions like a legal "receipt" confirming the delivery of documents from one party to another in a legal matter. Detailed documentation: After leaving the documents with the substitute server, the process server must fill out an affidavit of due diligence. Service is "the formal delivery of a writ, summons, or other legal process or notice" according to Black's Law Dictionary. The person who serves the papers on the Defendant must fill out the "Affidavit of Service" and return it to the Plaintiff signed and notarized.