For a business trip, you are going to have to hand in an official invitation letter by the parties living in Germany, fully explaining the character of your visit. For a tourist visa, you aren't going to be required to get any formal invitation letter of any type. You have to offer a photograph.
Post-exposure therapy and advice ought to be in accordance with national guidelines. After you have confirmed the details, you'll be prompted to put in your credit card details for our service charge.