US Citizens who are at least 21 years old, can petition their parents for the green card. The parents would be considered “immediate relatives,” meaning that a visa would be immediately available for them to immigrate.
If the parent is abroad, the US citizen would file an I-130 with USCIS. After approval of the I-130, USCIS will transfer the file to the Department of State. The Department of State will then collect additional documents and fees, before transferring the file to the appropriate US Embassy or Consulate. The parent would then apply for an immigrant visa at the US Embassy or Consulate, and would be processed for the green card upon entry to the US.
If the parent is in the US, the US citizen would file an I-130 and the parent would simultaneously file an I-485. USCIS may or may not require an interview, and will approve both the I-130 and the I-485 at the same time. The green card would issue shortly thereafter.
In order to avoid any mistakes, it is advisable that you have an attorney handle the process. Our Los Angeles immigration lawyers are available to assist you.