It's a key, what else do non-technical people need to know?
Ironically on macOS we used to have an app called Keychain which unfortunately was effectively renamed to Passwords for non-technical users.
The keychain and passwords app are separate and keychain still exists
I always operated under the assumption that the passwords app was just a more casual view into the keychain
Maybe that's a bad assumption
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It's a digital key.
Unlike physical objects they may reside in a TPM, a software vault, an export/backup, or any combination thereof. You may or may not be able to recover or migrate them, depending on where/how they were made.
Therefore you may need multiple per service, or maybe not. Services which only allow one may end up locking you out with no recourse. You get to find out.
None of this is obvious or self explanatory to normies.