The white bag in fair territory is the base a fielder should touch when making a putout at first base. This base is in place in softball in large part because of the number of bunting that occurs during the game. It helps to prevent collisions at first base. The rest of the rules are very similar to baseball. Again, it depends on the type of league a player is participating in.
Some leagues allow for a courtesy runner for the pitcher and catcher.
In addition some leagues allow for a 10th hitter in the lineup, which serves as a designated hitter, as long as both teams agree. There is no stealing or leadoffs, and pitches in most leagues that have an arc of below 6 feet or above 12 feet are considered illegal. If the illegal pitch is taken, it is automatically a ball, but a pitcher does have the option of hitting an illegal pitch. The strike zone is determined by where the ball crosses the plate in relation to the hitter and where it lands behind the plate. Generally if a pitch lands within the strike zone inside of the batter s box behind the plate, it is a strike.