DIAGNOSIS That's the internal relay clicking. It's normal, but can be audible in a very quiet room. It happens when the thermostat checks or adjusts the connection to the equipment wires, or when it polls connected sensors.
FIX There's no software setting to disable this physical sound. Your main option is to dampen it. Ensure the thermostat is seated flush and firmly on its wall plate—a slight gap can amplify the sound. You can also try putting a thin foam pad or a piece of felt behind the thermostat body (don't cover the vents) to absorb some of the vibration.
IF THAT DIDN'T WORK If the clicking is loud, rapid, and coincides with the system short-cycling (turning on/off every minute), that's a different problem. It means your equipment is shutting down on a safety limit (like a dirty flame sensor) and the thermostat is constantly re-engaging. That requires an HVAC service call.
HEADS UP You might hear a single, louder click when the thermostat actually calls for heat or cool—that's the relay engaging to send 24V to your equipment. The little periodic clicks are just it "checking in."