A green card is a permanent residence visa and gives a person the legal right to live and work permanently in the United States and to enter and leave the country freely. You can become a lawful permanent resident based on a family relationship, through employment or through the Green Card Lottery.
You can also work in the U.S. if you have a work visa. The most common one is the H1-B, which is valid for three years and can be renewed once. The first thing you should do is to find a job and get hired by an American company; the next step is for you and for the employer to process your visa. This can be time-consuming and expensive. An H1-B visa is tied to a particular company, which means you won't be able to switch jobs.
For a more detailed explanation of the paperwork necessary to obtain a work visa, we suggest contacting the American embassy or consulate in your home country. Also, unless you really enjoy the challenge of legal paperwork, we recommend hiring a legal advisor to assist you during the application procedure.
Please visit our Visa section for more details regarding green cards and work visas.
Given the difficulties getting the green card or a work visa, many people simply work illegally in the U.S. Although there are literally millions of illegal workers in the U.S., we do not recommend you to consider this option at all. Illegal workers are under constant threat of deportation and are often exploited by employers. If caught by the authorities, you can also be heavily fined and forbidden from entering the U.S. for years.
To get a legal job in America you need a social security number, which is issued to every American and legal immigrant. There is a lucrative black market for false documents, which can cost anything from a few hundred to thousands of dollars. Note that if you are caught working illegally, the consequences will be even more severe if you have been working on false documentation.