@Jeanette *********************
>meaning the employers letter must be address to .
The employer must write a letter to the consulate asking for the Non-B visa to be issued. Different consulates have slightly different requirements.
>And the requirements in getting back?
You will need a Thai pass, approved health insurance valid for 89 days (the length of the entry stamp from the Non-B visa), and booking at a test-n-go center.