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). Documents to prove Massachusetts Residency Requirement.For a REAL ID credential, two documents must be from this group. Most users should use Affidavit of Domicile (MPC 485). If you need to save a partially filled-out form, you may choose to use the alternative form:. US Passport or US Passport Card 2. Typically, in order to claim US domicile, the Affidavit of Support sponsor must be residing in the United States.