Assuming you are referring to a toy unicorn:
The best way to take care of your toy unicorn’s hair is to brush it regularly with a soft bristled brush. You can use a wide-toothed comb to detangle any knots or tangles. Be careful not to pull too hard on the hair as this could damage the roots. If your unicorn’s hair is looking dull, you can try giving it a ‘haircut’ with blunt scissors. This will help to get rid of any split ends and give the hair a fresh, healthy appearance.