Storing unhashed passwords in a database

Question

User identification

It was required to store passwords of users in a database.
The password is needed for authentication on a third-party service, so hashing is not suitable.
Tell me how to do it better?

Answer 1

1) Store session_tokens, unless of course the third-party service works through OAuth.
2) If not, encrypt with the key. Keep the key deep inside. So if the database is taken away, they will not decrypt it without the key.

Answer 2

Store encrypted (symmetrically or asymmetrically).
Take care of the encryption key.
Decrypt before use.