Steppers are special motors...where if you turned the shaft you would feel the detents or poles.....torque is generally higher at low RPM and rapidly decreases as the RPM increases.
Servos can be AC or DC motors...brush or brushless....torque is generally constant across their RPM range.
Drives or drivers are the electronics that cause the motors to spin....most of the hobbyist drivers are step/direction type....the professional drivers for servos are 0 to 10 volt.
Drives/drivers are matched by type (stepper or servo (AC, brushed, unbrushed)). The stepper drivers are further matched by how the windings for the stepper are driven (polar, bipolar, etc.) and each is matched based on operating voltage and current.