Form I-864 is required for most family-based immigrants and some employment-based immigrants to show that they have adequate means of financial support. Use this form to show they have adequate means of financial support and are not likely to rely on the US government for financial support.The Affidavit of Support is a form that establishes a sponsor's ability and willingness to financially support an immigrant in the United States. You, the sponsor (petitioner), and the joint sponsor must complete Form I-864. See tips for completing Form I-864. Line-by-line guidance for properly filling out USCIS's I-864 Affidavit of Support to sponsor an immigrating family member. In this video we're going to show you how to complete an i 864 and affidavit of support that is needed as part of the package for an adjustment of status. 1.e. I am the first second of two joint sponsors. Other Information. 1.f. Also include a physical address only if it is different than the mailing address.