Is it permitted for children to color for fun, or to use activity books where they stick on stickers on Chol Hamoed?
Children may color in an activity book or stick on stickers during chol hamoed. The reason is because it is considered tzorech hamoed, as it is a festive enjoyment, and it isn’t a maaseh uman ( a professional act). An artist however would not be allowed to just draw a painting on Chol Hamoed, because it is a maaseh uman.
Chag Kasher Vsameach
Hilchos Chol Hamoed (old edition) pg. 75.