ISO- The sensitivity of your sensor to light. Creative effect is noise. This means that the higher the ISO the brighter the light is.
Aperture- Good for really good exposure. Controls the amount of light which causes creative effect. Depth of field can be used by the aperture. This controls the focus.
Shutter Speed- Duration of light, creative effect and can be also used for motion.
Exposure is the term used in photography to measure the amount of light that passes though lens and hits the photosensitive material inside your camera. Now, the amount of light needs to be controlled. Otherwise, you’ll get a photo that is either too bright (over-exposed) or too dark (under-exposed) photo. Aperture controls the flow of light that goes into the camera. Shutter speed controls the amount of time that the light is allowed to stay on the photosensitive material. The ability to absorb light by the sensor is controlled by ISO.