A Green Card is the ability to establish permanent residency in the USA,

Essentially it gives a person the right to;
- Live in any part of the US and move freely in the US
- Work in any employment (as long as they are licenced to perform the duties involved for some jobs)
- Travel in and out of the US freely
- Access some social benefits
- Apply for US Citizenship after a period of 3-5 years depending on their nature of the Green Card
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