What kinds of social changes happened during World War I?

I am assuming you mean social changes in America during the war. The complete mobilization of the home front for the war effort brought significant changes to American society, especially for minority groups such as women, German Americans, and African Americans. President Woodrow Wilson mobilized the entire economy for the war effort, instituting the first draft (the Selective Service Act of 1917) since the Civil War and creating government agencies to oversee the production and distribution of food and fuel (oil and coal) and to coordinate and regulate industries to manufacture war materials, such as munitions and weapons.
Life for women changed drastically, both in the war effort and on the home front. Many women served as nurses, secretaries, and administrative assistants in the armed forces and organizations such as the Red Cross. On the home front, women filled the jobs men left behind when they went off to fight in Europe, especially in factories and war industries. In addition to entering the work force, women served important roles overseeing the war effort at home and in their communities. The federal government used propaganda to encourage food and fuel rationing and conservation. Because women often served as the primary shoppers and cooks in their families, conservation campaigns were often aimed at women. They were encouraged to observe meatless Mondays and plant Victory Gardens in order to conserve food for the war in Europe. Women's contributions to the war effort helped women gain the right to vote in 1920 with the passage of the 19th Amendment.
African Americans also experienced increased opportunities during World War I. During this time, the Great Migration of African Americans from the South to the North occurred as African Americans moved North to meet the labor shortages caused by the war. Like women, many worked in factories and jobs left behind by men who left to serve in the war. African American men also served in the US Armed Forces in large numbers, although they were forced to serve in segregated units. Some African American leaders such as W.E.B. DuBois hoped this service would lead to greater rights and equality for African Americans. Unfortunately, after the war, as soldiers returned home and expected jobs, racial violence often broke out in cities and led to the Red Summer of 1919. After the war, African Americans also experienced a cultural rebirth known as the Harlem Renaissance, as African Americans made great contributions to American culture in the form of music (jazz, Duke Ellington and Lance Armstrong, to name a few) and literature (the poetry of Langston Hughes, most notably).
Unfortunately, World War I also helped spur a repression of civil liberties. In 1917 Woodrow Wilson signed the Espionage and Sedition Acts. The Espionage Act made it illegal to interfere with the draft and the Sedition Act made it illegal to use "disloyal, profane, scurrilous, or abusive language" about the Constitution, the government, the American uniform, or the flag. The government prosecuted over 2,100 people under these acts, including labor leaders Eugene Debs and Emma Goldman. German Americans were particularly susceptible to prosecution. German Americans were regarded as the enemy and faced anti German sentiment during the war. Sauerkraut became "liberty cabbage" and frankfurters became "hot dogs." German Americans were also the victims of violent attacks. German was banned from being taught in public schools, and cities and streets that had German names were changed.