There are several ways through which you can become a lawful resident of the United States and obtain a Green Card and this Green Card will allow you to stay in the country as long as you wish, provided that you abide by the immigration laws of the country. The most easiest way to immigrate to America is through family based immigration and in this case, you will have to be sponsored by your family member who is a US citizen. Similarly, people who are hired by US employers who are also willing to sponsor the hired foreign workers for lawful status in America, will also become eligible for US Green Cards. Similarly, if you are granted asylum or refugee status in America, you can apply for and obtain a Green Card after living in the country as refugee or an asylee for a year.
To obtain a family based Green Card, you must be sponsored by your family member who is a citizen of the United States. In this case, the sponsor will have to file Form I-130 for you and prove that he will sponsor you financially in the United States. If you are currently in a foreign country, you must file an application for an immigrant visa after the USCIS approves Form I-130, filed by your relative. If you are in the United States on a non-immigrant visa and if your immediate relative files Form I-130 to sponsor you, you can file Form I-485 concurrently and adjust your status to lawful status and obtain a Green Card.
Foreign nationals who are sponsored by US employers will also become eligible for United States Green Cards. To get an employment based Green Card, you must be sponsored by a US employer for a US Green Card, who is offering you a full time job in the United States. Similarly, the sponsoring US employer must also file an immigrant petition for you. After Form I-140 filed by the employer is approved, you can apply for an immigrant visa in an overseas consulate and get into the United States with that visa and obtain a Green Card and live there as a permanent resident. Likewise, people who invest in business ventures in the United States will also become eligible for US Green Cards.
Citizens of certain foreign countries may take part in the official lottery program that grants Green Cards to the winners of the lottery program and obtain Green Cards. This program conducted every year by the US Congress, allows 50,000 winners of the lottery program to immigrate to the United States and obtain Green Cards. This will help people who do not have sponsors, to immigrate to the United States.