When you need to communicate with your students in a synchronous real-time fashion, sometimes a full blown video conference seems like overkill. This is especially true in a setting where there might only be a small number of students, or it is an impromptu meeting, or simply a situation where the ability to see and hear each other isn’t a high priority or necessary at all.
In such cases, a text-based chat may serve your needs better than an elaborate video based meeting, while also avoiding the use of resources that might be better served for a class that needs it.
The following video shows how to set up chat rooms in your Moodle page: