Heated Jacket

Hi,

I want to use the electric heating pad to heat up fabric in a jacket. I also want to be able to control the temperature of the heat. The pad needs 5V to heat and can go up to 12V. What I want to be able to do is hit a button and the battery will output a certain amount of V to the pad. If I hit another button, it can output let’s say 8V. I am new to this so I want to know what I need to make this happen.

Thanks, David