Anmeldung is the registration of your address with the local authority. The certificate often becomes part of later administrative steps, so an attractive short stay can create trouble if the host cannot provide a Wohnungsgeberbestätigung.
Ask before paying
Request written confirmation that registration is possible and ask who will issue the housing-provider confirmation. Check whether your name can appear on the letterbox; official post can arrive quickly. A booking receipt alone is not the same document.
Build in time
Appointment availability varies. Keep digital copies of your passport, completed registration form and provider confirmation, but carry originals when instructed. Official requirements can change, so check Berlin’s service portal rather than relying on an old forum thread.
Registration does not solve every residence or tax question. It is one administrative step whose timing should be considered alongside your lawful status, insurance and employment start.