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).On Form I864, petitioners must prove that they have the ability to financially support the visa applicant(s) if necessary. Some types of evidence you can share to show you intend to establish domicile include: Opening a bank account. Transferring money to a United States account. Completing and signing Form I-864 makes you the sponsor. Yes, an unemployed petitioner does need to file I864 when petitioning a husband along with the cosponsor.