The part of the electromagnetic spectrum usually used for communication is

The part of the electromagnetic spectrum usually used for communication is of  radio waves, infrared waves and microwaves.

But most common waves used in communication are radio waves.

Explanation:Radio waves are used to transmit television and radio programmes.While microwaves are used for mobile phones and Wi-Fi. Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies as high as 300 gigahertz (GHz) to as low as 30 hertz (Hz).