Smart heroes lie down when lead starts flying. They move, shoot, and then get prone behind cover before their action is over, forcing attackers to go on Hold to attack them. Prone gives them Medium Cover against most attacks. Ranged attacks within 3“ ignore the modifier since the target is just as exposed as if he were standing next to these characters.

If a prone defender is caught in melee, his Parry is reduced by 2 and he must subtract 2 from his Fighting rolls. Getting up from prone costs 2” of movement.

Savage Worlds Deluxe Edition p. 85