-It is prohibited to launder clothing on Chol HaMoed, by hand or via washing machine.
However, children’s clothing which often get dirty and soiled may be washed if necessary. (Shulchan Aruch Siman 534:1)
-It is prohibited to add any adult clothing into the washing machine along with the wash that is being done for the children. (Psak of Rav Moshe Feinstein Zatzal)
-Even for children, it is only permissible to wash those particular articles of clothing that are needed. (See Mishna Berura 534:11 and Aruch HaShulchan 534:8)
-The age of the children whose clothing may be washed, is at most until age 6 or 7 years old. (Psak of Rav Shlomo Zalmen Auerbach Zatzal in Shulchan Shlomo 534:3)
-Polishing shoes, brushing a hat, spot cleaning a stain[that developed on Chol HaMoed] and simple ironing to remove wrinkles to make the clothing wearable for Chol HaMoed is permitted on Chol HaMoed, according to most Poskim. (See Ram”a 541:3 and Mishna Berura S”K 9. See also Shulchan Shlomo 534:1 and Emes L’Yaakov 534: footnote 489)