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.The purpose of the Affidavit is to assist consular officers in determining whether a visa applicant will have adequate means of financial support in the US. 864 Affidavit of support How to fill out the Form 864 immigration Tips US mmigration with Attorney Jacob Sapochnick Form I-134 is a promise to financially support a person applying for a temporary visa to the United States, namely a travel visa or a K-1 fiancé visa. 864 Affidavit of support How to fill out the Form 864 immigration Tips. The "Affidavit of Support" is a signed document to accept financial responsibility for a family member who is seeking a green card. Submit a completed Affidavit of Support form. Sponsors who are US citizens and permanent residents should complete the USCIS Form I-134 Affidavit of Support. This form is one of the immigration forms that can be presented as proof of financial capacity at the visa interview.