A lawful permanent resident is someone who have been granted the privilege to live and work in America permanently. If you are a foreign national and if you seek to immigrate to the United States, you can get a family based Green Card, if you have an immediate relative in the United States, who is willing and capable of sponsoring you for a US Green Card. If you do not have immediate relatives in the United States who are US citizens, you will have to choose some other way to immigrate to America.
If you have an immediate relative in the United States and if that US citizen relative is ready to sponsor you, he must file Form I-130 for you and prove that he is also capable of sponsoring you financially in the United States. And to do so, your relative must demonstrate that he has enough income to support you. Followed by that, you and your sponsor will have to file few forms and complete certain steps in order to get into the United States.
Immediate relatives of US citizens and Green Card holders
Immediate relatives of a US citizen are his spouse, parents and his minor children. All the other categories of relatives are not immediate relatives and they come under the preference categories. In order to help an immediate relative to immigrate to the United States, the US citizen must first file Form I-130 for the beneficiary. The beneficiary can concurrently file Form I-485 for adjustment of status, if he/she is in the United States when the sponsor files Form I-130. After the approval of these forms, the beneficiary will be granted lawful status in America.
USCIS will mail the approved Form I-130 to the overseas consulate and after being notified by the consular officer, the beneficiary can apply for an immigrant visa, if the beneficiary is in a foreign country and with that visa he/she can immigrate to America.
Unlike immediate relatives of US citizens, immediate relatives of Green Card holders, will have to wait until visa numbers become available and they cannot file applications for immigrant visas until then.
Preference categories
Siblings, unmarried children above 20 years of age and married children of US citizens, also can immigrate to the United States, but they cannot immediately apply for immigrant visas and they will have to wait until the priority dates become current, after the approval of Form I-130 filed by their relatives. They can file petitions for immigrant visas, if they are in foreign countries or they can file applications for adjustment of status, if they are in the United States only after the priority dates in their immigrant visa categories become current. Nevertheless, this process will take years to complete.
Only the US citizens can sponsor relatives who are not immediate relatives the Green Card holders can sponsor only their spouses and children.