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. 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. 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). Learn how to prove your U.S. domicile for a family visa with our stepbystep guide. Essential documents and tips to ensure visa approval. Acceptable evidence to support their domicile claim. Completed Form I-864. Two (2) forms of proof of address must accompany your application.