Activity Completion tracking is a Moodle feature that allows each activity or item in Moodle to have a completion checkbox associated with it. Essentially, it lets you turn your course items into a kind of to-do list. You can allow students to manually mark items complete, or set specific criteria that students must meet for the item to automatically be marked complete.
Some benefits of using completion tracking:
In your course, click the gear icon, then Edit settings
On the Edit course settings page, scroll down and expand the Completion tracking heading. Change the Enable completion tracking dropdown menu to Yes.
Click Save and display to return to your course.