Can I plug my wireless system into any audio input?

You can, as long as you use the right kind of input. A wireless system works best plugged into a standard professional audio mixer. You can also connect it to powered speakers that have a built-in microphone or audio mixer.

Plug the system into a MIC input, not a LINE or STEREO input. Mic inputs are usually XLR or 1/4" jacks. Using a mic input keeps the signal level correct so your audio comes through clean instead of distorted or too quiet.