In the 1920′s women’s fashion changed radically. The war is over and there’s a relative feeling of times only getting better. The classic idea of having long hair is gone and society gets more looser and acceptable.
It must be noted that cutting the hair all short wasn’t done by everyone, coming from the long Edwardian looks, cutting of all of it wasn’t an easy decision. Many women cut their hair shoulder length. The bob is the most stylish hairdo, faking it was normal. Wild curls and hairpins were a woman’s best friend.
Women with naturally straight hair and an even more wilde spirit cut their hair short and banned the curls.
Art nouveau and Art Déco inspired accessoires like the headbands still exist, but wearing large hats is very out of style. Small hats are the way to go in the roaring twenties. Finger waves already existed before the war and are still an acceptable style.
It must be noted that styles were different from region/country and still even class.