Nary from Cambodia wants to visit China for 1 week

Dear Sir/ Madam,

I am Cambodian citizens holding valid passports. I am female and single. and never flight to China or Hong Kong before. Company in China wants invite me for training course for 1 week at his company and they will responsible for all expense during I am staying there. What other document needed for apply Visa? Please advice. Thank in advance.

From Nary,