Instructors can use Group modes to control how groups of students interact with an activity and what students can see from other groups.
Moodle has three Group modes available: No Groups, Visible Groups, and Separate Groups
Image from UMass Amherst site: https://www.umass.edu/it/support/moodle/group-modes-moodle
Set a Default Group Mode for Your Course
Instructors can set a default group mode for activities within the course in the course settings. When you set a default, each activity will show the default group mode but you can still change the group mode for activities if needed. Follow the instructions below to apply a default group mode for your course.
1. On your course page, in the upper right corner, select the gear icon and click Edit Settings.
2. On the Edit Settings page, navigate to the Groups section.
3. From the Group mode drop-down menu, choose a default group setting: No groups, Separate groups or Visible groups.
4. Next, click the Force group mode drop-down menu and select Yes. Forcing group mode will apply the group mode to every activity.
5.Scroll to the bottom of the page and click Save changes.
Note: Force group mode is usually used when more than one Academic Assistant is used in a course.
If group mode is forced to yes, students cannot participate unless they are assigned to a group. Click here to learn how to create groups in Moodle. In addition, see Assigning Students to Groups Manually for how to add students to groups already created.