Well, Touch screen is only an input device as it only takes the input resistance(or capacitance in new touch screens) value as per the touch on the screen. And this value of resistance would determine the location of the touch on the screen.
The output work is done by the LCD or LED displays, which displays some images and texts on screen.
Touch Screen is only a transparent glass which is place on that display and synchronized with the LED displays such that user is able to 'touch' or have a 'sense of touch' on the actual displays
