There are generally two categories of visas: immigration visas and non immigration visas. Visas are coded by a system of letters from A-V. Some examples of non immigration visas are tourist visas, student visas and fiancee visas.
The K1 fiancee Visa is a non-immigrant visa classification. The fiancee visa allows foreigners to come to the United States to marry U.S. citizens and live in the USA.
The foreign fiancee gathers the
paperwork, attends an interview, and
gets the K1 fiancee visa, travels to the U.S., marries in the U.S. and applies for adjustment of status during the first 90 days.
Read more about the K1
Fiancee Visa Processing.
fiancee visa forms explained
K3 Spousal Visa
When do you need a K3 Spousal Visa?
An US citizen marries a foreign fiancee in the USA or in another country, the foreign fiancee goes back to their country, the U.S. citizen applies to the Service Center for an I-130 spousal visa petition.
Live with your fiancee in the United States
Once your spouse has been granted a K3 visa, they will be able to come live with your fiancee in the United States. The K3 is a "multiple entry" visa, they can travel using their K3 visa, and they can obtain permission to work with their K3 visa. Once they arrive you should ordinarily pursue an adjustment of status application based on their pending immigration petition as soon as possible in order to help ensure that they become a legal permanent resident before their K3 visa expires.
It is also possible to secure permission for them to work related to their adjustment of status application, rather than simply relying on their K3 spousal visa. Similar considerations apply for your spouse's minor children if they come to the USA on a K4 visa. Read more about the K3 Spousal Visa Processing.