trip to Zhengzhou.Do I need an invitation letter if I go there just as a tourist?

I am planning to go on a two-week trip to Zhengzhou. I am going there alone, but I do have a friend there. Do I need an invitation letter if I go there just as a tourist? And, do I have to fill in the visa application form both ''questions'' 2.8 and 2.9? Or can I leave them out?
And another thing. Do I have to have a place to stay booked in advance? Because in the visa form application, under the number 2.5 I have to write the residence where I'll be staying. Is that necessary?
Thank you in advance.