While moving to a new city in Germany, you must always register in person after moving in at the Citizens' Registration Office. You can find further information on the Citizens' Registration Office of your city on the internet. There, you can also book an appointment online for your registration.
What you would need - in general - for your registration are the following documents:
- Identity document
- landlord confirmation (the so-called "Wohnungsgeberbestätigung")
homefully provides you with the document landlord confirmation ("Wohnungsgeberbestätigung"), that is needed for your registration. Check out this article for further information on your landlord confirmation.