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. A) Complete an Affidavit of Support form and; b) Gather evidence of their finances and other supporting documents (See Step 5).An affidavit of support, (USCIS Form I-864), is required for all immediate relatives of US citizens and lawful permanent residents. The "Affidavit of Support" is a signed document to accept financial responsibility for a family member who is seeking a green card. 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. 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. The required financial documentation is needed to issue your I-20 student visa eligibility certificate. If the intending immigrant will apply for an immigrant visa at a U.S. Embassy or Consulate overseas: Complete Form I-864 when it is mailed to you from the. Affidavit of Support.