Generally, you'll find them inside the door panel. To access them, you need to remove the interior door panel. Once the panel is off, the motor will be visible, usually attached to the window regulator mechanism.
To find the specific location, you'll need a repair manual or a detailed diagram for your 1993 Ford Explorer. These resources will show you exactly where each motor is positioned within its respective door. Online parts stores often have diagrams associated with parts you look up, if you know the window regulator part number.
Without specific knowledge of which window is malfunctioning, I cannot provide a more precise location.
