This guide will clarify what domicile is, how to establish it, and the documentation you need for proof of 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). Moving to Washington? Here's a checklist to get you ready. If you're planning to petition a family member for a green card, you'll most likely need to prepare Form I864, Affidavit of Support. All domicile must be established at least one year immediately prior to the first day of the quarter the student is seeking residency. Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States. Residence Questionnaire – Students complete page 1, and parents complete page 2 of the form.