An employer has to want to hire you for a job that qualifies for a visa. As part of the interview I need to share a job offer letter.My employer wants to write it but needs to know what all should go inside the letter. The offer letter to the Canadian employee have to indicate a "contract of employment for the full 3 years" of the TN visa. Mecklenburg County offers internship opportunities in many other departments as well. Search our current openings to see if you can find your match! Following is the letter format I got from my attorney. Is this OK to carry. A job offer is required and the U.S. employer must file an Immigrant Petition for Alien Worker, Form I-140, on behalf of the applicant. Title: Operator Maintenance.