Dear Applicant:
Thank you for your e-mail.
Previously, foreign travelers granted entry by CBP officials received a paper Form I-94 (Arrival/Departure Record). This process is now automated, with some exceptions. If you received a paper Form I-94 or I-94W and failed to turn in your paper Form I-94 Arrival/Departure Record to the commercial airline or CBP when you departed the U.S., see the CBP Website for instructions. Do not send your paper Form I-94 or I-94W to the U.S. Embassy or Consulate General.
If you received an admissions stamp in your passport instead of a paper Form I-94 when granted entry, the I-94 record was created electronically, and a paper copy was not provided to you. CBP will record your departure from the U.S. electronically. Learn more on the CBP Website.
If you have further question, please contact CBP directly.
Regards,
Non-Immigrant Visa Unit
U.S. Embassy Bangkok