I'll answer these questions out of order. As the product description says, the Zooka ZS720 only can throw baseball or smaller sized balls. It cannot throw softballs. That said, plenty of softball players practice with the machine because if you can hit a baseball, a softball looks HUGE coming from a live pitcher.
Any pitching machine on the market can throw a 6-12 foot slow pitch softball pitch. They all have up-down adjustments that can be made to the angle of the pitching machine head. It just takes some patience to get the angle of the pitching machine head and the speed adjusted so that it is throwing a perfect arc over the plate.