K-1 fiancé visa petitions are processed in the order received, and the time frame is based on the caseload of the field office handling the request, according to U.S. Citizenship and Immigration Services. Approved K-1 visa petitions are sent to the National Visa Center.
When the NVC receives the approved petition, a case number is assigned and a letter is sent to the U.S. petitioner advising that the petition was sent to the U.S. Embassy or Consulate located in the fiancé's home country, explains the U.S. Bureau of Consular Affairs. Next, the foreign U.S. Embassy schedules a visa interview with the fiancé.
The interviewing fiancé is required to take specific documents to the visa interview, including a completed Form DS-160, a valid passport, police certificates, medical examination proof and evidence of financial support. An incomplete set of documents may result in an administrative delay, advises the U.S. Bureau of Consular Affairs. Once all information has been provided, a decision is made whether or not to grant the visa request.