Family-based Visas - A U.S. citizen can file an immigrant visa petition for: a spouse, son or daughter, parent, and/or a brother or sister. A U.S. lawful permanent resident (that is, a green-card holder) can file an immigrant visa petition for: a spouse and/or unmarried son or daughter.
Employment-based Visas - A U.S. employer can sponsor certain skilled workers who will be hired into permanent jobs. In some specialized fields, U.S. law allows prospective immigrants to sponsor themselves. In addition, U.S. law provides a number of special immigrant categories, as well as an immigrant investor program.
Special Visas - There are other immigrant visa categories. A U.S. citizen can also petition for the immigration of a foreign fiancé(e) to be married in the United States, or an orphan adopted abroad/to be adopted in the United States. Several immigrant visa categories that cover special types of workers or special circumstances are established by U.S. laws. The United States also conducts an annual program for Diversity Visas.