The empirical formula tells us how many atoms of each element are in a molecule regardless of the structure of the molecule, that is, regardless of which element is bonded to which element or what type of bond there is. It is the simplest way to represent a molecule.
As far as I can see the molecule C6H12 is already represented by its empirical formula, so in this case, you don't have to use any formula. You know that there are 6 atoms of carbon and 12 atoms of hydrogen, that is the information that the empirical formula gives.
So, the empirical formula for C6H12 is C6H12