PWM input voltage regulation
PWM in itself is regulation.
You need an h-bridge if two direction rotation is needed and if you do not have (+ve)-GND-(-ve) power configuration available.

The robust design will use switching devices (possibly MOSFETs) with proper rating (with overload overhead) and inductor kick suppression (mostly already inside the MOSFETs) when you disconnect the pulsed power. Plus protection in the case electronics want to fry the metal, ceramics and plastic. ;)

PWM is filtered (averaged to DC) by the inductance of the motor coils but that has less to do the real performance; the real motor speed is the combined effect of the filtering of PWM and its moment of inertia. A motor with enough moment of inertia will filter out the PWM pulses mechanically if not done electrically.

You need one duty factor for PWM in one direction and another duty factor in the other direction.