I can think of at least 6 different ways headlights are wired these days. When you post a question without also listing year, make, model and engine, there is NO way anybody can give you accurate information. Re-post and include that critical info.

A front car headlight? Could be the bulb again. Depending on make and year, could be relay, DRL relay, switch, etc.

bulbs do fail. replace is and see if that was just a simple issue. the battery should not be related as long as everything else works.

Open the hood and look straight down at the top of the head-light assembly. Remove it and change the bulb.

Wiring, switch if you have ones that turn on by switch, my main guesses but that's something that needs to be looked at in person unless you know what you're doing

May be some wiring problems check the wires

OBD2 can tell you what failed. But you can check fuses. If there's no bad fuse or bad bulb, go to a service station.

It could also be a ground problem for that light

Wow youre a bright one... have you tried changing the light bulb?

WIRING. JIGGLE WIRES AT LAMP