Business visa application for Thai

Please advise if there are 2 Thai would like to apply for visa to enter to China for a meeting. Do they have to apply for visa by themselves or not ? Is it possible if the company has provided the power of attorney to the driver to apply for visa on their behalf ? How much does it cost and how long does it take ? Can I assign the driver to collect their passports on their behalf ?

Please reply to me as soon as possible.

Thank you.