How Can I Prove U.S. Domicile? Petitioners must submit evidence establishing the domicile requirement to the National Visa Center (NVC) along with the Affidavit of Support.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.. Completing and signing Form I-864 makes you the sponsor. Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States. This guide will clarify what domicile is, how to establish it, and the documentation you need for proof of domicile. A sponsor is required to be at least 18 years of age and domiciled in the United States, its territories, or possessions.