The software you are importing your seed phrase doesn't know if an additional passphrase exists (calling it a password is incorrect at best because the implementation is completely different, but unlike other cases, in this case, the implementation does matter since it helps you understand better how to not fuck up your setup), so if it is not engineered following best practices, it may even not offer you an option to specify it (a passphrase) when accessing a wallet. Think of a wallet created out of a combination of seed phrase and passphrase as something different from one derived from a seed phrase only: it will generate a piece of information completely unrelated to a single seed wallet so that all addresses, keys, and results of derivation path equations will be impossible to reconstruct without knowing initial passphrase. The reason this wallet is called "hidden" is likely due to the fact that it leaves no traces inside the wallet itself: inserted passphrase is not remembered or hashed, it creates temporary wallets that matter for a single session, and any passphrase is considered a "right" one regardless of whether it contains funded addresses or not.