The fiancé(e) K-1 nonimmigrant visa is for the foreign-citizen fiancé(e) of a U.S. citizen. The K-1 visa permits the foreign-citizen fiancé(e) to travel to the United States and marry his or her U.S. citizen sponsor within 90 days of arrival. You can learn more about fiancé(e) visas on usvisas.state.gov.

Personal appearances at the U.S. Embassy are by appointment only. 

Update on Executive Order 13769:

The provisional revocation of January 27, 2017, which had revoked all valid visas of nationals of Iraq, Iran, Libya, Somalia, Sudan, Syria and Yemen in accordance with Executive Order 13769, “Protecting the Nation from Terrorist Attacks by Foreign Nationals,” is now lifted, and those visas are now valid for holders otherwise eligible for their visas.  Anyone with a valid visa may now use it to travel to the United States and does not need to apply for a new visa.