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 addition to this form, sponsors should also send a financial statement showing sufficient funds to cover the students tuition and living expenses.This video will help you to fill out I-864 For Joint Sponsor. Sponsors of students planning to attend the University of Utah should complete the following form. You, the sponsor (petitioner), and the joint sponsor must complete Form I-864. See tips for completing Form I-864. What is a joint sponsor's liability under the Form I-864, Affidavit of Support? In today's video we are going to be filling out form i 864 the affidavit of support form for the joint sponsor. I was told that if my income is very low (which it is), a joint sponsor would have to fill out form I864 (affidavit of support). If you are filing Form I864 as the petitioning sponsor, use our How to Fill Out Affidavit of Support Form I864 guide.