What is the role of free electrones in electricity?

Electrons in the outer band can become free of their orbit by  the application of some external force such as movement through a magnetic field, friction, or chemical action. These are referred to as free electrons. A free electron leaves a void which can be filled by an electron forced out of orbit from another atom. As free electrons move from one atom to the next an electron flow is produced. This is the basis of electricity.This movement of electrones is called electricity.