A US Citizen can apply for a special temporary visa to allow a non-citizen (their fiancée) to enter the country in order to get married to a US citizen inside the US
If the non-citizen has children who are under 21 years old and unmarried, they may be able to come to the US as well. The petitioner needs to include their names on the I-129F, and they can get a K-2 visa.
After the non-citizen arrived in the US, he or she can immediately apply for permission to work by filling out a form I-765, Application for Employment Authorization.
