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. If you have a joint sponsor, they must also complete Form I864.You, the sponsor (petitioner), and the joint sponsor must complete Form I-864. See tips for completing Form I-864. If you are filing as a joint sponsor, then you will need a separate Form I-864 for each sponsor. Completing and signing Form I-864 makes you the sponsor. Line-by-line guidance for properly filling out USCIS's I-864 Affidavit of Support to sponsor an immigrating family member. The Affidavit of Support is a Contract between Sponsor and Household Member. The petitioning sponsor must sign and complete Form I-864, even if a joint sponsor also submits an I-864 to meet the income requirement. By signing Form I-864EZ, you are agreeing to use your income and resources to support the intending immigrant named in this affidavit, if it becomes necessary.