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. Completing and signing Form I-864 makes you the sponsor.Affidavit of Support: This is a statement of a sponsor's income, resources, and willingness to support an alien. You, the sponsor (petitioner), and the joint sponsor must complete Form I-864. See tips for completing Form I-864. Most family-based filings require an I-864 when sponsoring an immigrant spouse, child, sibling, or parent. 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. The I-864 is required in order to show that the sponsor – or joint sponsor – has adequate financial ability to support the immigrant beneficiary. The I864, also known as the affidavit of support, is a "4Part" form in the Green Card Process, whether Adjustment of Status or Consular Processing.