HOW CAN I REPROGRAME A NEW KEY?

I HAVE FOUND THE ONLY WAY TO FIX MY BROKEN KEY WAS TO GET A NEW KEY I HAVE FOUND THAT I NOW NEED THE CODE THAT COMES WITH THE CAR SO IT CAN BE REPROGRAMMED TO THE CAR THE ONLY PROBLEM IS I CANT GET THIS CODE AND WONDERED IF ANYONE KNOWS HOW OR WERE I CAN OBTAIN THIS FROM THANKYOU