On the Users page you can enable user login. Click Enable login system to enable this option. Three types of users then become available: Administrator, Operator and Custom. Per user you can edit the name and password. There is also an option to disable one or more users.
Once you configured these settings, the user icon becomes available in the upper right corner of your screen. Click the user icon to log out and sign in with a different user, with or without a password depending on how you configured the users.