You keep using that word...

Authorization and Authentication are often mixed up in the world of cybersecurity. Solutions that handle Access Management are often confused with Identity and Access Management tools. It totally makes sense because they kinda do the same thing but.... they don't.

Authentication is the process of verifying the identity of a user (think usernames, passwords and accounts)

Authorization is giving access to things based on the authenticated identity.

To be honest you could use either of these to control who has access to what system. When put together you can now get better understanding of what accounts exist, what they have access to and you now have a clearer understanding of what is going on.