The most important piece of an application for TN visa status is the employer's job offer / support letter. Regardless of the substance or contents of this letter, there are a few basic rules that should be followed to avoid U.S. immigration's rejection of this letter:

1. Applicants should always present a letter with an original signature. Copies of signed letters are normally rejected. Signatures should be in blue ink as they are more easily identified as originals.

2. The letter should be printed on the TN petitioner's company letterhead. Again, the letter should be printed in color to further assure the officer it is an original.

3. The letter should be addressed to the applicable U.S. immigration authority, e.g. U.S. Customs and Border Protection (for border applications), the U.S. Embassy/Consulate (for DS-160 applications), or USCIS (for I-129 petitions).

4. The letter should have a reference line or subject line indicating the applicable TN category.

5. The individual who has signed the letter should be prepared to receive a call from a U.S. immigration officer who may call to confirm the position offered.