You might have to remove the headrest in your Mustang for many reasons. You might be customizing your car, replacing the seat, or replacing a damaged headrest. This is not a complicated task, and it will only take a moment.
Kneel on the seat, facing the head rest.
Raise the headrest up as far as you can.
Press the button on the side of the housing that the head rest support bar slides into; pull the head rest completely out of the seat.