This plugin allows you to select multiple roles for a user – something that WordPress already supports “under the hood”, but doesn’t provide a user interface for.
User edit and Add new user screens will display a checklist of roles instead of the default role dropdown. The main user list screen will also display all roles a user has.
It also supports well Multisite mode.
That’s it. No extra settings.
If you want to contribute to this plugin, feel free to check the Github repository : https://github.com/chrneumann/multiple-roles