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. In today's video we are going to be filling out form i 864 the affidavit of support form for the joint sponsor.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. This video will help you to fill out I-864 For Joint Sponsor. If you are filing Form I864 as the petitioning sponsor, use our How to Fill Out Affidavit of Support Form I864 guide. In this guide, we will explain who needs to complete Form I864, when to file it, and how to fill out Form I864 stepbystep. It may not be necessary for his wife to sign Form I864A as long as he can provide sufficient evidence of his income and assets. Please fill out this form if you or another individual (like a family member) will be paying for your tuition and other expenses.