U.S. immigration law allows certain noncitizens who are family members of U.S. citizens and lawful permanent residents to become lawful permanent residents (get a Green Card) based on specific family relationships.

A spouse, minor child or parent of a U.S.Citizen qualifies as an immediate relative.
Other family members eligible to apply for a Green Card are described in the following family “preference immigrant” categories:

• First preference (F1) – unmarried sons and daughters (21 years of age and older) of U.S. citizens;
• Second preference (F2A) – spouses and children (unmarried and under 21 years of age) of lawful permanent residents;
• Second preference (F2B) – unmarried sons and daughters (21 years of age and older) of lawful permanent residents;
• Third preference (F3) – married sons and daughters of U.S. citizens; and
• Fourth preference (F4) – brothers and sisters of U.S. citizens (if the U.S. citizen is 21 years of age and older)

There is a two-part process for filing the Green Card of a family member for any of the categories mentioned above. 

 1) The first part entails the filing of Petition for Alien Relative with USCIS.

2) The second part entails filing of Adjustment of Status or doing Consular Processing.