I have a slider that goes out to a cement step, but it seems very low/deep to me. What is the lowest and highest a step should be? And can I pour another step over the existing one to make my step shorter?

Most steps are 7" to 7.75" in height in the US, slightly taller in Canada. This would be accpording to building codes but you can build them shorter if needed. What is the measurement from the top of the last step to the floor surface you end up on?