Immigration Consultancy Services in Delhi: An immigrant visa is a document that allows a foreign national to enter the United States and apply for permanent residence. There are a number of different types of immigrant visas, each with its own requirements. The most common type of immigrant visa is the family-based visa, which is available to close relatives of U.S. citizens and legal permanent residents. Other types of immigrant visas include employment-based visas, investment visas, and diversity visas.