When moving to Germany with the intention of staying for longer than three months contrary to a tourist, you need to register your address in person at the Residence Registration Office within two weeks of your arrival. De-registration when leaving Germany need not be done in person, but by filling out the respective form and by sending it to the Town hall. For further valuable information and forms available for download, please go to the website of Munich's Residence and Registration Office:
https://www.muenchen.de/rathaus/home_en/Department-of-Public-Order/Registration-Deregistration