"i was wondering if it is a "must" that you have to get a K visa in order to marry". No, in some circumstances, a K-1 (fiance) or K-3 (spouse) visa is not an appropriate visa when a US citizen marries or is already married to an alien. For example, if the alien is already in the US on a F-1 (student) visa, applying for a K visa likely is unnecessary.
The purpose of the K visa is to give the alien an opportunity to come to the US to either get married to the US citizen or to wait the final processing of the alien's immigration petition.
To be eligible to file for a K visa, the first requirement is that the person in the US must be a US citizen. There are many other requirements.
You should read the instructions to Form I-129F. The form and instructions are available for free at
www.uscis.gov . USCIS also publishes other articles explaining the K visa in more detail. You can search for the articles at
www.uscis.gov .
You can also consult an attorney who can review your facts and options with you.
Child support/student loan debt from Fiance
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My canadian fiance want to live in US with me
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