U.S. Customs and Border Protection

Form I-94 is the DHS arrival/departure record. The I-94 is an extremely important piece of your travel record and status while in the United States. You should have a copy of the actual Form I-94Arrival/Departure Record which provides evidence of your legal admission to the U.S. 

Each time you enter the U.S., you will be issued a new I-94. Immediately after each entry, you should go to the I-94 website to pull up the new I-94 PDF and PRINT a copy for your records and as evidence of legal entry.  
You are required to upload your I-94 record in iStart as proof of your arrival into the United States during the Mandatory Document Check-In process.
If you have been granted F-1 or J-1 status through a Change of Status process and do not have a visa stamp in your passport, you will receive an I-797 Approval Notice instead of an I-94 as proof of your status in the U.S.

Some items cannot be brought into the United States. Others may require permits, and yet others may only be restricted from certain locations. Read more information regarding Clearing Customs and Border Protection before you travel into the United States.

Under U.S. law, you can bring into, or take out of, the United States as much money as you wish. However, if it is more than $10,000, it must be reported to Customs and Border Protection. In addition, destination and transit country requirements may apply. Please read more about reporting currency on the Customs and Border Protection webpage.

U.S. Customs and Border Protection Resources

U.S. Customs and Border Protection Agency’s Currency Reporting Advice
U.S. Customs and Border Protection (CBP) "Know Before You Go"
U.S. Customs and Border Protection, Prohibited and Restricted Items