These additional financial sponsors also have to submit an Affidavit of Support, proof of their income, and proof of their legal status in the United States. 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).Providing proof of domicile in the United States is critical for most people when submitting Form I864, Affidavit of Support. Completing and signing Form I-864 makes you the sponsor. Upload the most recent version of Form I864 on USCIS website. Country of Domicile enter the joint sponsor's country of domicile (most sponsors will enter "US" as the country of their domicile). 6. 2. A copy of the sponsor's permit, permit to reside, certificate of permanent residence or other lawful authority to reside in The Bahamas.