It is a document that allows an individual to come to the United States temporarily and for a limited purpose. The period of validity of thesevisa varies from 30 days up to 10 years. An alien is allowed to apply for admission at the port of entry during the period of visa’s validity. You should understand that the visa’s period of validity is not the same as the authorized period of temporary stay in the United States. The authorized period of temporary stay is indicated in the Form I-94, Arrival-Departure Record. It may be less or longer than the visa’s period of validity.