Name  Petition for Alien Fiancé(e)
Purpose This form is used to classify your fiance for marriage to a U.S. citizen, and his or her children, to pursue adjustment of status to lawful permanent resident.
Agency USCIS (United States Citizenship and Immigration Services)

The Form I-129F is the first government form filed in the K1 visa process. It's important to file correctly to avoid delays known as RFEs. This form, as well as its instructions are available free from uscis.gov. This form was updated in April of 2017, with several pages added to the forms and instructions. As of June 9, 2017, the USCIS will no longer accept the previous version.