A fiancé visa / fiancée visa, called a K-1 visa, is a nonimmigrant visa which allows foreigners who are engaged to United States citizens to travel to America to get married.
After your fiancée enters the United States, and you get married, you have 90 days to file their Adjustment of Status or their immigration status will change to unlawful.
A CR1 visa, also called IR1 spousal visa, is an immigrant visa issued to an alien who is married to a U.S. citizen or permanent resident and wishes to live in the U.S. with their spouse.