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). How Can I Prove U.S. Domicile?You have to submit at NVC, NVC's job is to collect the documents for the consulate and make sure they are complete. In this post, we'll explore examples of proof of US domicile and the documents required to establish proof of domicile.