For an expatriate to legally work in Thailand, they must obtain and hold a work permit – either the blue book or the digital version. In order to do so, they must have a Thai company sponsoring their employment.
The application and renewal procedures and processing times, as well as the qualifications required to be met by the expatriate differ depending on the type of registration the company is under: General Business, Board of Investment (BOI), and Industrial Estate Authority of Thailand (IEAT). If the company is registered under BOI, then the expat is eligible to hold a “Digital Work Permit”.

It must be noted that the sponsoring company must have THB 2,000,000 paid up capital per expatriate employed. Also, there must be a 4:1 ratio of Thai to Foreign employees.