If you want to sponsor someone for a family-based green card, you need to provide proof of a U.S. domicile in your Affidavit of Support (Form I-864). My residence or business address is: On (date):.I served the following documents (specify):. What Is Proof of Personal Service? Official Forms for Viewing and Downloading. This guide will clarify what domicile is, how to establish it, and the documentation you need for proof of domicile. Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States.