I'm installing a stacked washer and dryer I will like to know the height of the washer hook-up and the dryer hook-up boxes

We set our washer boxes a few inches over the washers flood rim.
We like to give the stand pipe as much heigh(36")t as we can so we keep the trap as low as we can.
There is no minimum height of a receptacle whether dryer, range, refrig, or even a convenience receptacle. Good luck, Tom