Flash photography is the use of a camera flash bulb in a variety of possible situations where there doesn’t seem to be enough light. The most common use of flash photography is group portraits at gatherings where there is not enough light to take a satisfactory exposure.
The Shutter controls the time the sensor will be exposed with light. The longer the shutter is open, the longer time the sensor will be exposed. So what this means is that the aperture controls how much light the sensor can be exposed to and the shutter controls for how long the sensor will be exposed. The aperture and the shutter are together the most powerful tool to create your photograph the way you want it.