Head and shoulders pattern signifies farther downward movement when price breaks the neckline. In classical technical analysis the downward movement should be equal to the distance between the head and the neckline, although the real supports or resistances are a better way to define profit targets. We trade head & shoulders just like breakdowns.
Inverse head and shoulders signifies upward movement when price breaks the neckline. We trade them like breakouts.
Head and shoulders in WDC daily chart
Head and shoulders in SPY 1 hour chart