Check all the basics first. Fluid to start. Do you have any braking issues? Could mean you need to make some brake repairs. If you have easy access to the mechanism (like on older pickups and cars with the ebrake peddle) check and make sure everything is functioning right. Used to have an old pickup that would not retract all the way unless I released the handle a 2nd time.
The parking brake switch can also activate that light. In addition to what was mentioned above, it’s also worth checking the operation of that switch if you don’t find anything fluid or fluid level related. More info on solving brake problems here.