Those which allow electricity to pass through them easily are called conductors.

They have free electrons to move inside the material.

E.g. : Metals, human and animal bodies and earth are conductors.

Those which doesn't allow electricity to pass through them are called insulators.

Most of the non-metals like glass, porcelain, plastic, nylon, wood offer high resistance to thepassage of electricity through them.

When some charge is transferred to a conductor, it readily gets distributed over the entire surfaceof the conductor. In contrast, if some charge is put on an insulator, it stays at the same place.

When metal rod is rubbed with hand, no electric charge is obtained because charges on metalleak through our body to Earth.