How did the US respond to the economic needs of fighting during WWII?
There were three major ways, generally speaking, in which the US government responded to these economic needs. There was rationing, there were government efforts to ensure that companies produced the things that were needed, and there were major attempts to get people to loan money to the government.
The government set up the Office of Price Administration to make sure that the public did not use too much of various commodities. The OPA instituted rationing for many things such as rubber and gasoline.
The government also set up things like the War Production Board and passed the Smith-Connally Anti-Strike Act. The WPB did things like halting the production of passenger cars so that materials would go, instead, to war production. The Smith-Connally Act ensured that strikes would not disrupt war production.
Finally, there were many war bond drives meant to persuade people to lend money to the government. This money was, of course, used to fund the war effort.