What is input overlay?
Input Overlay is a setting that shows on-screen controller graphics on your screen, letting you watch the inputs you perform during a match.
How do I add inputs to OBS?
From the Sources menu click the + symbol to add a new Source. You can then add your incoming audio from your audio interface to the Sources so that your audience can hear you. Please select Audio Input Capture from the Source menu, select Add Existing and the Mic/Aux channel, and click OK.