If you need to control the result of the task, activate the Check task upon completion option in the task settings. Once the responsible user marks the task as completed, it will be sent over for you to review. You can accept the task or return it for revision.
To enable this option, open a task and click Edit.
Then click Options next to the Deadline field.
Tick the box next to the Check task upon completion option and save the changes.
As a task creator, you will be notified when a user completes the task.
If you are not satisfied with the results of the task, you can return it for revision.
When all is well, you can accept the task as completed.