The I-94 is the Arrival/Departure Record issued by the U.S. Customs and Border Protection (CBP) when you enter the United States. Your I-94 record confirms that you have been legally admitted to the United States in a specific visa status, and for what duration of time.
CBP has traditionally issued a paper I-94 that will resemble the sample below.
However, CBP more recently has begun using electronic I-94 records that can be retrieved online. An example is pictured below.
If you are having trouble locating your I-94, go to Where can I find my electronic I-94 record?