You must obtain a letter of invitation. The organization you will be visiting is responsible for obtaining the invitation. A copy is acceptable. This letter must: be written on company letterhead, include the full local address and phone number of the organization or person to be visited, request the same validity of visa as in the Business Introduction Letter, and specify the number of entries you are requesting for your visa.
You are required to provide a Business Cover Letter from your U.S.-based company. All letters must be printed on company letterhead that displays a U.S. mailing address. Use the included sample Business Cover Letter to complete your letter.