License fee for general public access to radio & television
After having registered with the Bürgeramt directly after your arrival, you will eventually receive a letter from an organization called “ARD ZDF Deutschlandradio Beitragsservice” (formerly known as “GEZ” or “Gebühreneinzugszentrale“) concerning the Rundfunkbeitrag, which is a license fee for general public access to radio and TV channels.
The Beitragsservice is the state-run organisation that collects fees for radio and television under public law. Every household (with very few exceptions) must pay these license fees.
In Germany, there are many different radio and TV stations. Some of them are run by commercial companies and are called private stations; others (e.g. ARD, ZDF, Deutschlandradio, and the regional stations) are under public law. The private stations obtain their financial means from commercials, whereas the public stations are financed by the state and through the Beitragsservice license fees. They broadcast fewer commercials (none after 8 p. m.) and try to keep a higher standard of programming.
Now when you get that letter from the Beitragsservice you will find enclosed a form in which they ask you to register your household. Then you are usually asked to transfer the fees to a certain account using a direct-debit authorization. A special form for this purpose may be enclosed in the same envelope; or you will receive that later. If you do not approve of this direct-debit, you can also transfer the money in single units every month (either one at a time or by standing order).
Find here more information on the Rundfunkbeitrag in English.