On Form I864, petitioners must prove that they have the ability to financially support the visa applicant(s) if necessary. 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).This form and one of the following documents must be submitted to show proof of Nevada residency. All documents must indicate name and Nevada residency address. A proof of residency letter is an acknowledgment or sworn statement stating that an individual resides at a specific address. Download a proof of residency letter template for family members, notarized or non-notarized, tailored for legal use.