You can review task progress for tasks you assigned to someone else.
On the navigation bar, click Tasks.
Click View > Change View > Assigned.
Assigned tasks are missing
If you’re not seeing tasks you’ve assigned, Outlook might not be set up to keep copies of tasks you assign.
Click File > Options > Tasks.
Under Task options, check the Keep my task list updated with copies of tasks I assign to other people box.
Turning on this option doesn’t track the tasks you’ve already assigned, but it will track any new ones you assign.