If not submitted to NVC along with the Affidavit of Support form, the petitioner will need to provide the visa applicant with evidence of his or her domicile. Providing proof of domicile in the United States is critical for most people when submitting Form I864, Affidavit of Support.This guide will clarify what domicile is, how to establish it, and the documentation you need for proof of domicile. How Can I Prove U.S. Domicile? Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States. You have to submit at NVC, NVC's job is to collect the documents for the consulate and make sure they are complete. 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).