Electricity can be static, like what holds a balloon to the wall or makes your hair stand on end.
Magnetism can also be static like a refrigerator magnet.
But when they change or move together, they make waves - electromagnetic waves. Magnetic and electric fields of an electromagnetic wave are perpendicular to each other and to the direction of the wave. James Clerk Maxwell and Heinrich Hertz are two scientists who studied how electromagnetic waves are formed and how fast they travel. Different kinds of electromagnetic waves have different wavelengths.