Applying for visa via post or another person

Hello,

if I am visiting a foreign friend that lives in China and then continuing as a tourist, what type should I apply for? She is ready to send me a letter of invitation, but do I have to have an accomodation resevation and a route for other places I want to visit?
Second, I am currently staying in another country (not close to any of the consulate or embassy) untill the day of my departure to China, is it possible to send all the documents for the application via post to Croatia or maybe deliver all the documents by another person? Thank You in advance!