What kind of docutation is needed to fly to China from USA ? What if I decided to stay for 30 days or more ?

You'll need your passport, the application form, photos for the visa and of course the fee, to apply for a tourist visa to China. You can request a stay of longer than 30 days when you apply, here's the Chinese Embassy website which has all the information and downloadable forms to apply for your visa, good luck:

http://www.china-embassy.org/eng/hzqz/zg…