When an electric current flows through a wire, the wire gets heated up. This phenomenon is known as the heating effect of electric current.
Some applications of this effect are:
a) A filament is a thin wire inside a bulb that produces light. When electricity passes through this wire, there is high obstruction to the flow of current. Due to this the filament gets heated, ultimately making a bulb glow.
b) Various other electrical appliances where this principle is used are iron, electric heater, electric geyser, toaster, etc.