Do I understand correctly that the second address is the address for the Bitcoin cash? It turns out that I am automatically assigned an additional wallet?
It is the same address.
You were in possession of BTC at the moment btrash forked from bitcoin. Therefore you have these same amount of bcash associated to the same public key (accessible with the same private key).
The funds are assigned in the blockchain. No one created a wallet for you.
If you are interested in accessing them, you need to download a bcash wallet and import your private key into it. But better first move your BTC funds to a new address to be on the safe side.