Energy is defined as the ability to do work. There are different forms of energy. Some examples of energy are light, sound, mechanical, potential, kinetic, electromagnetic (such as UV, gamma, x-rays, microwaves, etc), chemical, and electrical. Energy can be changed from one form into another. However, energy can never be created nor destroyed. This is a universal law known as the law of conservation of energy.
The forms of energy that are listed above are used constantly within daily life. However, in response to your question, I will simply list three uses of energy below.
1. Light energy is used during photosynthesis to convert carbon dioxide and water into glucose (a sugar) and oxygen gas.
2. Sound is a form of mechanical energy due to the vibrations between molecules. Sound is used during sonar to map the ocean floor or communication between organisms.
3. Microwaves are used to heat our food.
I hope this helps!