How to Change Camera Height on Player Controller

I think that's under the local avatar - center eye anchor, or one of the eye anchors.  The prefab comes with multiple cameras attached to those anchors.  I've had success putting my camera as a child of the eye anchor.  I think that offset is the distance from the center eye anchor to the hand/controller anchors but not entirely sure.  Hopefully the eye anchors point you in the right direction.