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).The petitioner may fill out an Affidavit of Support, Form I-134. Line-by-line guidance for properly filling out USCIS's I-864 Affidavit of Support to sponsor an immigrating family member. Learn about the I-134 affidavit of support form, its requirements, and how to complete it. Ensure your visa application process is smooth with us. 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. 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 form I-864 is not required for K visas.