Many U.S. airports have discontinued stamping passports with an entry stamp when you enter the U.S. Instead, each time you enter the U.S., the U.S. Customs and Border Protection (CBP) creates an online, electronic entry record to record your entry to the U.S. This is called your I-94 record.  The I-94 record will be your only official record of entry to the U.S. 

You should check and save a screenshot of your I-94  record each time you enter the U.S. as the I-94 record is the only official evidence of your entry into the U.S. and you may need it for other purposes. If the I-94 record ever displays incorrect information, or cannot be found, please contact your HIO Advisor.