Please provide original Dispatch Letter. You can see the example here
Employment letter in English.
Original Employment Letter from Chinese company in English languagewith official letterhead（all the below information must be mentioned）:
• Full name, address, phone&fax number, email address of Employer;
• Name, position, tenure, salary of Applicant;
• Duration and Reason of Absence (the purpose must be clearly stated);
• Who will be covering the travelling expenses;
• It should be clearly stated that the applicant’s position will be retained, the company will guarantee that the applicant will obey all the local laws and finishes the trip as scheduled time;
• Signature by Responsible Person (his/her Position must be stated);
• Official Stamp.