The tourist (L) and transit (G) visas are the only ones that you can apply for without assistance from a business, government or academic institution.
Most visitors to China will only require a tourist L which will allow them to travel freely in most parts of China as tourists. If your situation is not described by one of the other visa types, then this should be the one you need.
If you are travelling in an organised tour group you might not have an individual visa in your passport. Instead, the tour group will be issued with a group L. The invitation letter issued by the travel agency is required. In such situations you will supply your details to the travel agency before you travel and then you have no further concerns. If you are travelling to Hainan province in an organised group you might also find that no visa is required.