Which of armed forces did join joined ww2?

During World War II, the major armed forces that joined included the United States Army, Navy, and Air Force, which entered the war after the attack on Pearl Harbor in December 1941. The British Armed Forces, consisting of the Army, Royal Navy, and Royal Air Force, were also significant participants from the war's onset in 1939. Additionally, the Soviet Red Army played a crucial role after the USSR was invaded by Germany in 1941. Other nations, including those in the Commonwealth and various Allied nations, contributed their armed forces as well.