In Germany, you must register your apartment with one of the many Berlin Bürgeramts within 14 days of moving in to your apartment, including moves within Germany. You must also de-register if you leave Germany. It is not possible to register by post but you may make an appointment online at any of the Berlin Bürgeramts.
General Required Documents
After you register you will receive your confirmation of residence registration. This document is required for opening a bank account, applying for residence permit, etc.
Anmeldung einer Wohnung - Service Portal Berlin