PWM In a stepper motor
If you use bbipolar stepper motor, it has two phases, so you drive it with two PWM signals at least. In more advanced aapplications- two PWM per phase, so four.  I wonder, if you know, where to connect this signals... I think, you should start with DRV8811, then you need one GPIO for direction and another one for step. No PWM rrequired.