The involuntary actions to stimuli are known as reflex actions. They take place without the conscious brain regions being involved. Reflex acts are all automatic behaviours. The brain and spinal cord of the central nervous system are involved in the reflex activity.
Alternatively, voluntary actions are those that are controlled by the cerebellum of the brain. As we get older, we learn to walk. The brain directs walking, which is done consciously when needed.