How does organisms store energy

Organisms store energy by adding a phosphate group to ADP which produces ATP.

Organisms have a wide variety of ways to store energy. Though they all produce the same energy molecule, ATP, it cannot be stored in this form. Instead, they usually store energy in carbohydrate form. For instance, in mammals, this can be identified as fat which stores high amounts of glucose (a type of carbohydrate) that can be later transported throughout the body and locally converted to ATP. Plants can also store energy in the form of glucose in fruit.