Answer:
The green card is one which would officially change the status of an immigrant to a Permanent United States Resident. The card is basically known as the United States Permanent Resident card but is commonly known as green card for the reasons of its color that it had previously had. The card serves as an identification for immigrants which would relate their identity as US resident. It looks like a drivers license, complete with photograph. The documentation is issued by the INS (now called the Department of Homeland Security).