

Dear sir/madam
Yesterday I was in the china embassy to apply for a tourist visa to mainlan China. I was asked to have a letter from the person who is inviting me there. I want to know 1) should the letter be in Chinese or English? 2)The inviter should be Chinese or from any country and nationality (The person I am going to visit is a friend of mine who is Iranian and has a business company in Beijing)? 3) What should be the content of the letter? 4) Should it be a letter admitted by an officia organization or it is just a simple letter written by the inviter?
I also want to know whether I can post my documents or I have to sumbit the documents directly (in person): I am Iranian, student in Uk and I have a temporary residence card of Portugal?
Regards
Shahabi