invatation letter from china local goverment office is not required for China Tourist Visa Application, you can apply for China Tourist Visa if you want to visit Shanghai, China, the requirements are:
1. Original passport with blank visa pages and validity of more than 6 months;

2. UAE resident visa valid for more than 6 months. (Excluding non-GCC applicants);

3. Application Form which must be completed neatly and signed by the applicant;

4. One passport photo (and the photos of the applicant's accompanying persons included in his/her passport if they plan to travel with the applicant.);

5. A No-objection letter from the applicant's company stating his or her position ,monthly or yearly salary;