The K1 visa allows your fiance(e) to enter the United States so that both of you can marry and live together in the United States. To apply for a K1 visa, you and your fiance(e) must be legally free to marry. The following are the legal requirements for k1 visa:

• Lawful citizen or of the United States Of America. Permanent residents are not allowed to apply for K1 visa.
• Met your fiance(e) in person within the last 2 years prior to filing for visa. You must also prove that the relationship is in good faith and both of you are serious about the relationship.
• You and your fiance(e) are of marriageable age. Both of you have expressed genuine intentions to marry each other and will do so within 90 days of your fiance(e) arrival in the United States.
• You and your fiance(e) have met the minimum income requirement – 125% above the poverty level.
• Your fiance(e) is a lawful citizen and possess no immigration or domestic law violations. No criminal records.
• Your fiance(e) posses an international passport.

If you and your fiance(e) fufils all these requirements, then you may obtain a K1 visa by making a I-129F Petition to the United States Citizenship And Immigration Services (USCIS). The following items should be included with your I-129F petition:

• Check payable to the Department Of Homeland Security. Do not make payments to USCIS as it is under the Department Of Homeland Security. Payment fees are for visa application processing, medical examination and other administration fees
• Prove that you are a citizen of the United States (birth certificate, passport, etc)
• Documentary evidence of your relationship with your fiance (photos together, passport stamps, etc) and also statements from you and your fiance(e) expressing the intentions to marry each other within 90 days of your fiance(e) arrival in the United States
• Biographic information of you and your fiance(e). This is done by filling out Form G-325A
• Evidence of you and your fiance(e) financial status (tax payments, bank statements, etc)
• Passport size photos of you. Passport size photos of your fiance(e)

Additional documents or information may be requested by the reviewing officer but generally, the above are the standard items required for most cases. Assuming the application proceeds smoothly with any hiccups, the length of time from the start of application to finally getting the K1 visa is about 6-8 months. This time can be delayed if applicants does not submit the relevant information or submit incomplete information.