A lawful permanent resident is a foreign national who has been granted the privilege of permanently living and working in the United States. If you want to become a lawful permanent resident based on the fact that you have a relative who is a citizen of the United States or is a lawful permanent resident, your relative in the United States will need to sponsor you and prove he/she has enough income or assets to support you, the intending immigrant(s) when in the United States.
For an overview of the types of immigrant visas available under immigration law, please see Visa Types for Immigrants. Your relative sponsor and you, the intending immigrant, must successfully complete certain steps in the immigration process in order to come to the United States. Here are the key steps:
First, the USCIS must approve an immigrant visa petition, I-130 Petition for Alien Relative filed by your sponsoring relative for you. Next, most sponsors will need to demonstrate adequate income or assets to support the intending immigrant, and accept legal responsibility for financially supporting their family member, by completing and signing a document called an Affidavit of Support. Once this is complete, then the intending immigrant will apply for the immigrant visa.
-Dept of State