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. Download the Sample.An affidavit of support, (USCIS Form I-864), is required for all immediate relatives of US citizens and lawful permanent residents. Step 1: Fill out the forms: If you have an existing case, no matter how old, use the same case title. 864 Affidavit of support How to fill out the Form 864 immigration Tips. 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. You will need your contact information, date of birth, social security number, and Medi-Cal number. Santa Clara County Affidavit of Surviving Spouse Form. Fill in the blank form formatted to comply with all recording and content requirements. You may also need this information for your spouse, guardian, or contact.