Admission to the US as an F-1 student is evidenced in most cases by a Form I-94 that reflects the date and class of admission. There are both paper and electronic versions of Form I-94. It is highly recommended to print your I-94 each time you re-enter the US to ensure you have been entered into the US on the correct Visa type, F1.
F-1 students are granted the electronic version of the Form I-94. To access the electronic, I-94 record, go to the I94 - Official Website (dhs.gov) website. Select "YES" to agree to the terms and enter the required information. This electronic record includes your most recent arrival record and I-94 number but also your travel history on the passport number you entered. If you have any issues retrieving your I-94, make sure you are entering your name as it appears on your passport machine readable zone at the bottom of your passport. If you still cannot retrieve your I-94, please contact the ISS Office for assistance.