Rookie Contractor Help needed! Adding a door to the garage.

Hi Guys,

I would like to replacing the existing window into a entry door.

The problem is there is a 12inch high and 8inch wide foundation at the bottom.

I wonder if I can cut the foundation off to fit-in my standard 82*30 sized door.

My main concerns is the will cutting of that 30inch wide foundation will cause

any structural damage to my house.