Completing and signing Form I-864 makes you the sponsor. 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.You, the sponsor (petitioner), and the joint sponsor must complete Form I-864. See tips for completing Form I-864. Form I864EZ is divided into nine parts. The information below will help you fill out the affidavit. In today's video we are going to be filling out form i 864 the affidavit of support form for the joint sponsor. The affidavit of support is a contract between the sponsor and the federal government. When a person files an I-130, they will usually file Form I-864, Affidavit of Support, as well; In many cases people file Form I-864 after filing Form. The I-864 is required in order to show that the sponsor – or joint sponsor – has adequate financial ability to support the immigrant beneficiary.