Visiting the United States
Generally, if you want to visit (and not live in) the United States you must first obtain a visitor visa. Travelers from certain countries may be exempt from this requirement. If you want to travel to the United States for reasons other than business or pleasure, you must apply for a visa in the appropriate category. This includes if you want to study, work as a crew member or journalist, etc., You can get help determining which visa you need by selecting the appropriate categories on our home page.
Extending Your Visit
If Customs and Border Protection (CBP) authorizes your admission to the United States at the designated port of entry, you will receive a stamped Form I-94, Record of Arrival-Departure. If you wish to stay beyond the time indicated on the Form I-94, you may apply for an extension by filing Form I-539, Application to Extend/Change Nonimmigrant Status, with USCIS.
Adjustment of Status
If you want to change the purpose of your visit while in the United States, you (or in some cases your employer) must file a request with USCIS on the appropriate form before your authorized stay expires. For instance, if you arrived here as a tourist but want to become a student, you must submit an application to change your status.
Until you receive approval from USCIS, do not assume the status has been approved, and do not change your activity in the United States. For example, if you are currently a nonimmigrant tourist, do not begin attending school as a student until you have received authorization from USCIS to change your status. If you fail to maintain your nonimmigrant status, you may be barred from returning to and/or removed (deported) from the United States.
In general, you may apply to change your nonimmigrant status if you were lawfully admitted to the United States with a nonimmigrant visa, your nonimmigrant status remains valid, you have not violated the conditions of your status, and you have not committed any crimes that would make you ineligible.