Many people get green cards through family members. You may be eligible to get a Green Card as:
• An immediate relative of a US citizen, this includes spouses, unmarried children under the age of 21, and parents of US citizen petitioners 21 or older
• A family member of a US citizen fitting into a preference category, this includes unmarried sons or daughters over the age of 21, married children of any age, and brothers and sisters of US citizen petitioners 21 or older
• A family member of a green card holder, this includes spouses and unmarried children of the sponsoring green card holder
Green card through a job
• Green card through a job offer: You may be eligible to become a permanent resident based on an offer of permanent employment in the United States. Most categories require an employer to get a labor certification and then file a Form I-140, Immigrant Petition for Alien Worker, for you.
• Green card through investment: Green cards may be available to investors/entrepreneurs who are making an investment in an enterprise that creates new US jobs.
• Green card through special categories of jobs: There are a number of specialized jobs that may allow you to get a green card based on a past or current job, such as:
Afghan/Iraqi translator
Broadcaster
International organization employee
Iraqi who assisted the US government
Panama Canal employee
Physician National Interest Waiver
Religious worker
-shanghaidaily.com