How is an element completed?

Based on due date or tasks, your elements will show a progress status bar to show you how near to completion the element is

Element completion is satisfied as a result of the completion of all checklist tasks within the element.

If you add a due date to an element that has no existing checklist tasks, the app will automatically add an "Element complete" checklist task to the element. This auto-added checklist task can now be edited in the usual way (the basis is that an element requires at least one checklist task to be "completable" for an element "due date" to have meaning).

Once all checklist tasks within the element are ticked, the element will then be marked as complete in all relevant dashboard reporting tables.

See also How do I schedule (or remove) a due date to an element, stage or grid?