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. 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. Individuals immigrating through most family-based, and some employment-based,1 visa petitions are required to submit an Affidavit of Support on. The "Affidavit of Support" is a signed document to accept financial responsibility for a family member who is seeking a green card. In this guide, we will explain who needs to complete Form I864, when to file it, and how to fill out Form I864 stepbystep. This form is required in most familybased green card applications, including CR1 and IR1 spouse visas and some employmentbased green card applications.