A) Your hand or emergency brake is on
or
B) You have a problem with your braking system.
A is easy to fix by releasing the brake
B Needs to be looked at by a person with mechanical knowledge to find out what is causing the problem.
Brakes are the things which stop you so any potential fault should be taken seriously.
The brake light on is usually a warning but could be something as simple as the sensor being out of position. I've seen that happen on cars that were driven out of the garage with new brakes. Sometimes it's a warning that the parking brake is on and other times, a warning that the fluid is low. With so many options, you should have it fixed and if you have to drive, use extra caution.
Make sure your emergency brake is off (all the way down). Add some brake fluid. If the light is still on, take it to a mechanic.
If the above answer on the emergency brake does not solve the problem, then you need to have the car checked. Your master cylinder could be failing, which means your brakes will fail. A failing master cylinder (or power assist unit) will not always leak brake fluid to the ground, so you cannot rely on looking for a leak. Or it may just be a problem with the sensor on the emergency brake, which is less of a problem.
Apparently you do not know how to compose using sentences. You have two mashed into one. How are we to decipher this code? What "brake light?" Do you not have an owner's manual, parents, adult family members, a local auto repair shop, etc. with whom to ask? Brand, model, miles, features, all necessary data is missing. "The brake light is on. Is it safe to drive?" By all logic ANY brake issue make the car UNSAFE to be driven. By ALL logic.
Take your emergency brake off, the light will go out.