Family based immigration visas are reserved for relatives of U.S. citizens and lawful permanent residents. The two qualifications to obtain a family based visa are 1) to not be inadmissible, and 2) to prove the immigrant has a family relationship with a US citizen or permanent resident. Depending on whether the sponsor is a citizen or permanent resident and the type of relationship the immigrant has with the sponsor, the relationship falls under "immediate" or "preference" relatives.
