The Exposure Triangle is made up of 3 components that are fundamental to taking good photos.
APERTURE: Controls the amount of blur or sharpness around your subject. The aperture that you set impacts the size of that hole. The larger the hole the more light that gets in – the smaller the hole the less light.
ISO: Senses the right amount of light for the visual effect you want. The ISO determines how well exposed a photo will be by changing the sensitivity.
SHUTTER SPEED: Shows the movement of a fast moving subject or freeze it in action. It's how long your camera spends taking a photo.