The main contribution of women to World War I (at least in the United States) was that they worked in war industries. About one million women participated in what you might call "war work." They did things like working in armament plants, machine shops, and steel mills while the men were away.
Women also contributed in more traditional ways. These included organizing drives to sell war bonds or get donations to help people who had been hurt by the war. They also helped to save good and other things that were needed for the war effort.
Women played a major role in the course of world war one. They had taken up jobs in the war industries and factories, and worked in places like ammunition factories, steel plants and many other manufacturing plants, while men were enlisted by the military forces to fight for their country. They had helped support the country while the men are out there fighting their hearts out to defend their homeland, so this shows that women's responsibilities had increased and their expectations about their role in society had changed, implying that they could do the kind of work that only men had been allowed to do before the war started.