How do I adjust the cutting height on my Sun Joe Mow Joe MJ401E Lawn Mower?

Power down and unplug the lawnmower.
Remove and empty the grass bag.
Place the lawnmower upside down so that you have a full view of the four wheels.
The wheel axles can be placed into 3 different cutting heights: Low ( will cut grass the shortest), medium and high.
Move all four wheels to the desired cutting height by pulling back on the rod axle and set your desired wheel height. Make sure all four wheels are at the same height.
Place the lawnmower back on its wheels and re-attach the grass bag.
Plug back in your mower and resume normal use.