In order for a Canadian and Mexican foreign national to enter the United States as a TN nonimmigrant, or to change his nonimmigrant status to a TN nonimmigrant status if he is already in the United States, he must either appear at a Class "A" Port of Entry, or his prospective or current employer must provide to the appropriate USCIS Service Center, the following documentation:

  1. Proof of his Canadian or Mexican citizenship;
  2. A letter from the prospective or current employer describing in detail the activities to be performed to show they are in a professional capacity, affirming the professional activity to be engaged in, the purpose of the TN nonimmigrant's entry, the anticipated length of his stay, the beneficiary's educational qualifications, the beneficiary's compliance with applicable state law, and what arrangements have been made for remuneration.
  3. Any diplomas, degrees, certificates or professional memberships required in the requested position. If the TN nonimmigrant's degree is a Canadian or Mexican degree, then he must have an evaluations of it if a degree is required.

Note that unlike Canadian foreign nationals, Mexicans foreign nationals are first required to obtain a TN nonimmigrant visa (as opposed to simply entering the United States in a TN nonimmigrant status). The Mexican foreign national TN applicant need only submit the request for a TN nonimmigrant visa at the U.S. embassy or consulate that has jurisdiction over his residence (or at another U.S. embassy or consulate that processes third country nationals) with a passport and a nonimmigrant visa application form, a letter of employment from a U.S. employer that indicates the position in question and why the position requires a professional. Again, as above, the TN nonimmigrant visa applicant must also present evidence that he is a professional.