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. The "Affidavit of Support" is a signed document to accept financial responsibility for a family member who is seeking a green card.A letter of invitation or Affidavit of Support is not needed to apply for a nonimmigrant tourist visa. 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. The form must be completely filled out. Completing and signing Form I-864 makes you the sponsor. OPTIONAL: if you will be providing any support for your family, download the I-134, or Affidavit of Support. USCIS form I134 Affidavit for support is required to file for officially sponsoring anyone for a US visa or immigration. More information on filling out an Affidavit of Support is provided lower on this page. A copy of the Affidavit of Support form .