Promotebutton in the Actions section. If it is disabled that means that the task has not been reviewed and verified.
Closebutton in the Task Editor. The button is available in three states: Open, In progress, and Verified. When the button is clicked, a dialog pops up asking to confirm that the user surely wants to close the task. Pressing
Closeends up inactivating the task. From this point it cannot be reopened anymore.