Admins have permissions to mass close goals by 1) navigating to the "Admin" panel in the navigation bar, 2) clicking on "Goals" on the left-hand side, 3) clicking on the "Auditing" tab, and then 4) looking under "All Goals."
From here, you can use the filter table to filter for specific goals (ie: end date). Once you have filtered, you can choose "Complete displayed Goals."
This will move all the Goals from "Active" to "Ended." Please note: the goal progress will remain the same.
For example, the following Goal has been completed, which you can see by the "Ended" date in the goal. However, the goal progress and any updates will remain the same from that point in time.