The North America Free Trade Agreement among the United States, Canada and Mexico (NAFTA) provides for the exchanges of goods and services between the NAFTA countries. The United States allows nationals from Mexico and Canada to work in the U.S., providing professional services. However, the visa is intended primarily for professionals in certain fields, specifically listed in the NAFTA treaty. One of the advantages of the TN visa is that the application process is more flexible and affordable than that of other work visas. For example, the TN visa does not require approval from the U.S. Citizenship & Immigration Services (USCIS) and can be processed directly at the American consulate nearest to your home in Mexico, or at any Port of Entry in the case of Canadian applicants. For Mexican citizens, the duration of the visa is one year, but it may be renewed indefinitely as long as the petitioning company continues to demonstrate the need for applicant’s services and the applicant does not intent to permanently reside in the U.S.
The H-1B visa is the standard professional work visa in the United States. One may be eligible for an H-1B visa if the job position typically requires a bachelor’s or higher degree and the employee has such degree or equivalent experience in the field related to the position. The law cites the following as clear examples of H-1B eligible professions: Architecture, Engineering, Mathematics, Physical Sciences, Biotechnology, Medicine and Health, Education, Law, Accounting, and Business Specialties. Currently, the U.S. government only allows 65,000 new H-1B visas per year (plus 20,000 reserved for those holding a US advanced educational degree, such as a Master’s or Ph.D.).
Another distinction of the H-1B visa is that it requires the employer to pay the visa beneficiary the "prevailing wage" for the corresponding professional classification in the area of employment, and the approval of the U.S. Citizenship and Citizenship Services prior to visa issuance at a consular post.
This type of visa is very useful for executives and managers who are already working abroad for a “qualifying organization”, which includes an affiliate, parent, subsidiary or branch of a U.S. company. The employee to be transferred to the U.S. must have been working continuously for the foreign company for at least one of the last three years in an executive, managerial, or specialized knowledge position. Likewise, the employee must be transferred to the U.S. with the purpose of occupying a similar position.