Headlights wont turn on

Check list for fun!
how old are the bulbs? are they broken? burned? new?
Have you been in an accident that may have caused come issue either physical damage or electrical problems?
Is everything connected any loose wires?
The lights are automatic or not? If you have to turn them on manually is the lever or knob functioning properly?
it could be very simple or a bit complicated. Hope that by checking these areas you are able to discover what the issue is. Also another thing to keep in mind is are the other lights working well? Good luck!