The Absentee Affidavit is to be completed if an applicant is unable to appear personally before the County Clerk to apply for a marriage license. A marriage license may be obtained from any county clerk's office.Many Texas counties now offer an online application process. This legal document serves as a testament to the bona fide nature of a couple's marriage, often a deciding factor in immigration cases. An affidavit of marriage is a legally binding document that proves a legal marriage exists between two people. An affidavit of marriage is a legal document and a sworn statement submitted to the court or another institution, to verify that two people are married. Affidavits are normally used in court proceedings or government agencies.