There are two ways you can mark a Task as closed or complete.
Closing a Task from the Task Details
1. Click a Task title to open up the full details of the Task.
2. On the right hand side, click Mark as Done.
Closing a Task from the Task page
1. Go to the Tasks page.
2. Click the checkbox beside the Task you want to mark as done.
You can re-open a completed task at any time!