American in Bangkok: How to get an invitation letter for L Visa?

If you don't have the invitation letter, you need to offer round-trip air tickets, hotel booking reservation and itinerary for the L type one. If you have one invitation letter, you needn't provide the above documents. The invitation letter can be from authorized Chinese organizations, companies, Chinese individuals or any foreigners who have valid visa in China. You can ask your foreign friends or Chinese friends to give the invitation letter or ask a Chinese travel agency to do it for you. I am afraid that the travel agency won't issue an invitation letter to you unless you join their tour.