Naturalization Certificate (or naturalisation) is the legal act or process by which a non-citizen of a
country may acquire citizenship or nationality of that country. It may be done automatically by a statute,
i.e., without any effort on the part of the individual, or it may involve an application or a motion and
approval by legal authorities.
A citizen of a foreign country who seeks to enter the United States generally must first obtain a U.S. visa, which is placed in the traveler’s passport, a travel document issued by the traveler’s country of citizenship.