After the form is completed, upload, and submit the signed form to NVC via CEAC along with the sponsor's supporting financial evidence. 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? These documents help us evaluate your application and verify your answers are true. This guide will clarify what domicile is, how to establish it, and the documentation you need for proof of domicile. Proof of U.S. domicile is required for the I864. Learn examples of proof of domicile along with proof of domicile documents required. Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States. Prospective immigrants residing in the United States submit an Application to Register Permanent. Residence or Adjust Status (Form I-485).