When I move thermostat to heat nothing happens no usual click from the furnace. Fan works checked breaker pilot is on.What is the part in the furnace that the thermostat turns on to start the heat and or what else could this be

Take off your t-stat and touch between r-w with a wire and see if it comes on.

Did that nothing happened no low voltage spark

Check to see if you have 24 volts coming out of you transformer