What kind of invitation letter do i need for a multiple entry visa valid for one year

Can you tell me the purpose of coming to China, for business? for tourism? If you want to get a multiple entry business visa to China, you have to provide one of the below documents:
1. multiple entry Invitation Letter of Duly Authorized Unit or Confirmation Letter of Invitation
2. previous two business visas in the last year

If you want to get a multiple entry tourist visa, you should statisfy one of the below conditions:
1. Your spouse is Chinese, provide passport of your spouse, the resident permit or the visa and the certificate of relationship statement
2. you have real estate in China, provide the certificate of ownership statement (copy).
3. previous two tourist visas in the last year