This guide will explain how to prove domicile when filling out Form I-864 ("Affidavit of Support"). Consular processing support without the high price tag.We recommend completing Affidavit of Support forms on a computer or typewriter, with answers typed in CAPITAL letters. 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). On Form I864, petitioners must prove that they have the ability to financially support the visa applicant(s) if necessary. You are required to obtain the original or certified copy, and one photocopy (with the exception of your passport and photographs) of the following documents. Learn the meaning of domicile in U.S. immigration and its implications. Understand its relation to the visa application process and immigrating to the U.S..