To open a German bank account, you generally need two things.
The first one is an identification document such as a passport or, if you're a EU resident, your national identity document.
The second item is a proof of residence, which in German is called "Meldebescheinigung".
If you're not yet in Germany but are based in the European Union, you can open a bank account with a bank such as bunq. Bunq won't ask you for a proof of residence in Germany, meaning you can get a German bank account without an address here.