A public address (PA) system consists of loudspeakers and an amplifier with a built-in mixer. You can connect microphones to the amplifier for use with the PA system. The problem with this set-up is you need to run a cable between the microphone and the amplifier, and, over long distances, this can require an extremely long cable. To eliminate the mess of the cable, you can use a wireless microphone system.
Insert the male end of an XLR cable to the output jack on the back of the wireless receiver.
Connect the female end of the XLR cable to an available input on the amplifier/mixer of the PA system.
Turn on the PA system, then turn on the wireless receiver.
Turn on the wireless microphone.