For Thailand BOI companies, after your prospective foreign employee got a visa (Non-Immigrant category B or IB) and entered the country, you will be able to apply for his work permit. You need to get his position approved first by filling out the detail of the position on Thailand BOI E-expert system website. After the Board of Investment approves the position, you will have to request the BOI to put your foreign employee into the approved position, again, on BOI E-expert website. You will need to upload his resume, passport copy, visa page copy, etc. His permit of stay in Thailand must have at least 15 days left. Once approved, you will get 3 letters from Thailand Board of Investment, one addressed to your company, the other two are for giving to the work permit desk and the immigration desk at the One Stop Service Center. They will issue a work permit book for the foreign employee with detail of his position, the employing company, the expiration date, etc. On the same day, you will submit the letter and his work permit at the Immigration Bureau at One Stop Service Center for extending his permit of stay in Thailand until the expiration day of his work permit.