This visa is available for foreign fiancés of U.S. citizens who are planning on entering the U.S. to marry their U.S. citizen partner and live in the U.S.
There are three steps in the K-1 Visa process: filing an I-129F Petition for Alien Fiancé with USCIS, filing all required documents with the National Visa Center, and passing your interview at the embassy local to your foreign fiancé
Once approved, the visa allows your foreign fiancé to stay in the U.S. for 90 days. During that time, you can legally marry before filing the green card application.
Your foreign fiancé must live outside of the United States.
Both partners must be legally free to marry.
You must have met in person within the two years before filing the I-129F.