Affidavit. A written statement of facts. The author of the statement must swear an oath that the facts in the statement are true.An affidavit is a written declaration under oath, made without notice to the adverse party. An affidavit is a written statement made under oath that is typically used in legal proceedings. Learn their purpose, when to use, and how to write. A written statement that someone makes after promising officially to tell the truth. An affidavit can be used as proof in a law court. An affidavit is a type of legal document that contains a written sworn statement. The religious institution's "definition and explanation" of an employee's role "in the life of the religion in question is important. Complete the appropriate employment forms (refer to your appointment letter for instructions on how to complete all necessary paperwork).