Canada/Mexico TN visas for USA work stays 3 year duration

This is the easiest visa for Canadian citizens and Mexican citizens to stay as a contracted person in USA.

The TN visa can be utilized as a work training contract.

- an agreement signed by an employer of a USA company and a letter stating the full or part time employment opportunity is enough to obtain a TN visa. Compensation is outlined in the agreement by employer example OSE and accepted by employee(sub contract/OSE participant)

The person seeking a TN visa will need to have a business registered in Canada or Mexico.

TN visa application can be done at any custom office(international airport easiest) after arrival in USA. Visa does not have to be applied for before 1st visit. Enter normally as a tourist.

-e.g. After 2 week course participant decides to stay for a longer duration. OSE agrees to creating an agreement. At that time after agreement is signed. The participant can go to any international airport (Kansas City) Goto a normal customs office in the airport and present documentation for employment and that is it, Visa complete.

Only Mexican or Canadian citizens can do this.

The TN visa, established under the USMCA, allows Canadian or Mexican citizens to work in the United States in prearranged professional-level business activities in designated occupations such as engineers, scientists, computer programmers, and other professions listed under the agreement.

Canadian or Mexican citizens do not need to obtain a TN visa in advance; they can apply for TN status upon arrival at a U.S. port of entry by presenting required documentation, including a letter from their employer detailing the position, purpose of employment, qualifications, and intended duration of stay.

Spouses and unmarried children of TN visa holders may enter the U.S. on TD status, though non-Canadian family members must apply for a TD visa

https://www.uscis.gov/working-in-the-united-states/temporary-workers/tn-usmca-professionals