The best answer is by breaking off a phosphate group from its structure.
ATP adenosine tri phosphate. It has three phosphate group attached to adenosine, hence the prefix "tri" for three.
During metabolism, a phosphate group is removed from ATP and energy is released for use by the cell. When this happens, ATP becomes ADP or adenosine di phosphate, "di" meaning two, i.e. adenosine remains with two phosphate groups. ADP is the core component of ATP.
A phosphate group is added again to ADP to make it ATP which is the form in which energy in the cell is temporarily stored before the whole process is repeated again
