If you are traveling independently (without an official tour group), you need to get an invitation letter. It is a little bit trickier than when traveling with a group or for business. Tour agencies supply the letters for their travelers and business travelers can obtain invitation letters from one of the companies they are visiting.
If you are visiting someone – or know someone – in China, this person can write you an invitation letter. (Find out what information the China visa invitation letter should include.) The letter will need to include dates of travel and intended time of stay. It should be noted that you can change your plans after getting your visa. The letter is a statement of intent, but Chinese officials will not check back on the information after the visa is issued. So, even if you are just in the planning stages, you can have your friend write you an invitation letter stating you will be staying with him or her and then you can change your mind after the visa is issued.
If you are backpacking or traveling on your own and don’t have anyone to write you a letter, you can use an agency to help you get a letter. One agency that is recommended is Panda Visa (this agency can also process the China visa for you).