Help with range attacks

So I have my mob, but how do I make it so it can melee attack from like, 6 blocks away? So far, I've gotten it to where if the mob touches its target, it hurts the target, but how do I make it hit from farther away? Please help.

Also, I've tried to make the attackspeed of a zombie disguised as a player higher, but that does nothing, here is my code:
Options:
PreventOtherDrops: true
Despawn: false
PreventItemPickup: true
MovementSpeed: 0.4
AlwaysShowName: true...

Help with range attacks