If you are an immigrant residing in the USA, you will need to get your Green Card to be able to work and have a legal domicile in the United States.
Is it possible to hold a second nationality if you're American, or if you come from a foreign country and you wish to become a U.S. citizen? Find out here.
Application for US citizenship by naturalization is a long procedure requiring perfectionism. Here are things you need to do to make yours successful.
If you are a foreigner married to a US citizen, you can apply for a marriage green card and become a legal US citizen within a few months.