USCIS Form I-134, Affidavit of Support, is a statement completed by U.S. citizens and lawful permanent residents (green card holders) to show their intent to support non-U.S. citizens financially during their visit in the U.S. This document is often used for visitor visas and tourist visas where the beneficiary's financial situation does not avoid the risk of being found inadmissible to the U.S. as a likely public charge. The U.S. government needs to see the foreign visitor will not become a liability, will not need to find a job, or seek public benefits - however, approval of the affidavit does not guarantee the issuance of the visa.
This form was released by the U.S. Citizenship and Immigration Services (USCIS), a component of the Department of Homeland Security. The latest version of the form was issued in February 2019 with all previous editions obsolete. You can download a fillable I-134 sample through the link below.