Welcome to the group. The front mud flaps are essential and should be part of the base vehicle.
They keep the Twizy clean and stop spray being directed into the cab. Easy to fit but don't bother with the supplied instructions. Easier to remove the existing Mud Guard then the front wheels. Then you can work on a bench indoors if required. The nuts can be a bit fiddly.
Tell us more about your Twizy.