How did the US support the Allied forces during the first two years of WWII?

In the first two years of the World War 2, the US was following the policy of isolationism i. e. US was not directly involved in the war from 1939 to 1941.

But US had to change its policy after Japanese attack on Pearl Harbour in 1941 and the US got involved in the World War 2 with a policy of expansionism.

World War II (1939-1945) has been the major conflict in the history. Although the United States did not enter the war until 1941 because President Franklin D. Roosevelt declared that the United States would maintain a formal neutrality; the US supported the Allied forces (Great Britain, France and the Soviet Union) during the first two years with the Neutrality Act of 1939 that stated that nations could buy guns as long as they paid in cash and sent their own ships, this policy was called "Cash and carry".