Standard height for the shower valve the handle that turns the shower on can be roughly waist high 36 inches above the shower floor or as high as 48 inches.
Shower valve height from floor.
I find if you have a shower valve fitted over the bath then 1300mm off the floor is a good height.
Check local building codes looking up local building codes is a great starting point if you want to install your shower valve at the right height.
Height above floor the minimum height for the shower controls area is 38 inches above the floor.
For shower stalls install the valve at the standard height of 48 inches or 4 feet.
A height of 28 inches or 2 feet 4 inches is standard for valves in bathtub shower units.
For shower only controls between 36 and 48 inches from the floor is common.
If valve is over a shower tray in a cubicle then around 1m from top of shower tray.
Employ your helper to hold the fixture at an estimated height and then see if it s a comfortable reach for all users.