Energy is defined as the ability to do work. There are many types/ forms of energy such as kinetic (the energy of movement), potential (stored energy), sound, mechanical ("muscle" power), electromagnetic (light, gamma, UV, IR, x-rays, microwaves, etc.) and nuclear. Energy cannot be created nor destroyed (this is called the law of conservation of energy). However, energy can be transferred (changed into) from one form to another.
The food that we eat contains chemical energy. We use this energy to perform daily activities (mechanical energy).
Likewise, the fossil fuels that fuel our cars also contain chemical energy within their chemical bonds. When the fossil fuels are combusted within the engines of the cars, the chemical energy is released to move the car (mechanical and kinetic energy).
A third example of how energy is used in everyday life would be nuclear power plants. Nuclear energy is the energy locked within the nucleus of an atom. Nuclear energy plants force atoms to undergo nuclear fusion (combining of nuclei) and then fission (splitting of nuclei). As the nucleus undergoes fission, energy is released that can be used in our homes or in power plants (such as factories).
Fourthly, light and microwaves (electromagnetic energies) are used daily within households.