Write a formal letter of invitation The person you should invite to the conference is an international expert. You need to locate this person and your letter should explain to her or him {and to me when | mark the assignment), why this person is important at the conference. The key-note speakers are invited through a business letter. Unlike the regular participants, the key-note speakers do not have to pay a conference fee, and their trip and accommodation are paid for by the conference organizers. Make sure that you get all titles and general information right