Enable Group Submission
Visit the Assignments tool
Select the Assignments tool from the Tools Menu in your site.
Click Add to create a new assignment
Or click Edit to edit a draft assignment
Note: You can only select the group submission option for a new or draft assignment. Once the assignment has been posted for students, you cannot change this setting.
Select Group Submission - One submission per group
If you select the radio button for Group Submission - One submission per group, it will allow any member of a group to submit an assignment on behalf of the other members of the group. By default, the same grade is applied to all group members when the item is graded. However, the instructor can also override the group grade for any individual member of the group.
Note: You must have existing groups in your site in order for the group option to appear.