How to Get a Green Card through a Family Member Who is Already a Green Card Holder
To promote family unity, immigration law allows permanent residents of the United States (green card holders) to petition for certain eligible relatives to come and live permanently in the United States. A permanent resident may petition for his/her spouse and unmarried child(ren) of any age to immigrate to the United States. Congress has limited the number of relatives who may immigrate under these categories each year so there is generally a waiting period before an immigrant visa number becomes available. If your family relationship qualifies you as an eligible relative of a U.S. permanent resident, then you are in what is called a family preference category.