Why is clicking a pen an example of mechanical energy?

The spring of a retractable pen stores the energy we provide through our clicks and puts a constant upward load on the refill.

Mechanical energy is the energy that is possessed by an object due to its motion or due to its position.

mechanical energy is often defined as the ability to do work, which means, its mechanical energy enables that object to apply a force to another object in order to cause it to be displaced.