How does a solenoid convert energy from one form to another?

A solenoid is a device comprised of a coil of wire, the housing and a moveable plunger (armature). When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in. More simply, a solenoid converts electrical energy into mechanical work.

Explanation:

The coil is made of many turns of tightly wound copper wire. When an electrical current flows through this wire, a strong magnetic field/flux is created.

The housing, usually made of iron or steel, surrounds the coil concentrating the magnetic field generated by the coil.

The plunger is attracted to the stop through the concentration of the magnetic field providing the mechanical force to do work.