You can tailor access to activities and resources by Groups or Groupings of students using Restrict access settings. For example, you may have some students get early access to an activity or resource, or some students who are allowed an extended deadline.
A grouping is a collection of groups within a course. Using groupings allows you to direct tasks at one or more groups in your course, so that they can work together on the tasks.
See more on this Moodle link(Groups )
Create groupings
To add a new grouping, select the Groupings option in the Participants drop-down inside a course and select Create grouping.
Add a Grouping name and, optionally, a Grouping ID number to and Grouping description. The optional grouping ID number may be added for matching the grouping against external systems or when when importing groups into groupings. Grouping ID numbers are not displayed anywhere on the site. Within a course, all grouping ID numbers must be unique.
See more on this Moodle link( Groupings )
To be able to restrict an activity, resource or course topic to a group, Restrict access must be enabled. This will result in a 'Restrict access' section in the activity, resource or topic settings and a group restriction can then be added.
To be able to restrict an activity, resource or course topic to a grouping, Restrict access must be enabled. This will result in a 'Restrict access' section in the activity, resource or topic settings and a grouping restriction can then be added.
Ensure that the Restriction by grouping option is enabled in the Restrict access settings; otherwise the Grouping button is not shown in your list of available restrictions.