How can I enable logging of user logins and logouts?

Click Settings in the administration area.

Now click on General.

Now scroll down until you reach the Audit log.

On this page you can configure which events should be logged. These logs can be found in the menu item "Audit log".

By clicking a user has logged in or a user has logged out you can also log whether a user has logged in or logged out. Activate your desired functions and confirm by clicking Save.