Can you recommend a tour company? How do I know if it is licensed by Chinese Government?

In my opinion, the TravelChinaGuide is an excellent company, which focus on providing the tourism service for foreign visitors. They have good operators, which can help you to arrange the whole journey when you in China. They have outstanding guides, who can accompany you during the journey.
As for details, you can check this website: https://www.travelchinaguide.com/about-us/ .