If you plan to travel to Germany and Europe, to visit relatives, participate in a summer school or work seminar then Schengen visa is the way to travel in Germany and all the European states that are part of the Schengen agreement.
With the Schengen agreement countries in Europe decided to gradually abolish border controls, and make movement of people much easier.
With a Schengen visa you can travel and stay not only in Germany, but all 26 countries that participate in the Schengen Agreement for a period of up to 90 days:
Completed application form in English and German only
Passport size photographs (see visa photo requirements for details)
Valid national passport
Bank statements for the last three months
Confirmation letter from your health insurance stating coverage for emergency medical treatment with a minimum of €30,000
Reference letter from your employer
Proof of group travel/hotel reservation/airline reservation and one copy
Your driver’s license and/or utility bill in your name as proof of residence in the consular where you plan to apply for the visa