A citizen is an individual who possesses the nationality of a nation. In most nations, the right to vote is commonly restricted to residents of the country.
The United States although given some polling rights to the immigrants from different countries by providing them Permanent Resident citizenship if they qualify the criteria to become the citizen of the country. However, they can only vote in regional and state elections for which they do not require the individual to be natural born American Citizen. It is very important that they do not vote in federal, state or regional elections that need a voter to be a U.S. citizen.