There are different ways of getting the green card (lawful permanent resident status) in the U.S.Among these are through family members such as U.S citizen spouse or U.S Citizen children 21 years and above,through employment, diversity visa lottery,asylum,investment in the U.S and lastly through cancellation of removal if in deportation proceeding.From the limited facts you have given,it is assumed you are not in removal/deportation proceeding.To be eligible for permanent resident status, you have to fall into any of the above categories and meet any additional legal requirement for that particular category. I hope you find the above helpful !