See also: User access levels, How to manage users
In Juju, a user is any person able to log in to a Juju controller.
A user logs in to a Juju controller using a username and a password.
Juju users are not related in any way to the client system users.
A user’s username and password are entirely different from the credentials referenced in juju commands such as add-credential—those are about access to a cloud, whereas these are about access to a Juju controller.