Do I need to have an LLC to apply for a DTV visa as a freelancer in Thailand?

A freelancer from Taiwan is considering applying for a DTV visa for himself and his wife. He inquired whether it is necessary to establish an LLC or if being a sole proprietor would suffice. He also wanted to know how many months of income documentation are required. According to responses, an LLC is not required and it is mentioned that applicants need to provide 6 months of bank statements showing a minimum balance of 500K THB when applying from Taipei.