Tourism Visa Reequirement

Dear Sir,
I have got offer letter from one comapany in Guangzhou China. Before Joining I have to attend one seminar that will be from 21st march to 25 march 2018. I already got invitation letter, What else documents required for my Tourism visa from Pakistan (except Original passport and Application).
Also I want to know how much time it will take, as Currently I am working in Dubai, I would like to go from Pakistan.
Thanks