Tourist visa for the Sri lankan

Dear sir,
My name is Kanchana ranasinghe I'm chairman of the kandy view hotel . I have travel all around the world this Christmas I was planing to go to holiday for china this is first time visiting to china has a tourist visa according to your web site I have a make my all documents ready . The invitation letter from my friend also from kuming when I come to the embassy officer talled me the letter need to stamp by the government . Please let me know which department my friend have to go and stamp . Please looking forward to hearing from to your answer .

Kanchana