Hi I am from Pakistan but living and working in Thailand since near 5 years.

i would like to visit one of my supplier in China but Bangkok embassy advise to ask Supplier to prepare some special "Invitation letter certified by Chinese Govt." as this is my first trip and i heard from supplier that it's hard to apply that type of letter could you please advise if i go back Pakistan to apply does i still need that type of Govt. Authentic invitation letter or can i use normal invitation letter issued and stamped by our supplier.