How did the united states contribute to the allied war effort in europe?

In both world wars, the U. S played major roles both in physically participation in it, and financing it. For most part of both wars the U. S attempted to stay neutral but it supplied and financed countries it had strong economic ties with. But during WWI, German submarine warfare destroyed too many cargo ships carrying American passengers which changed the attitude on neutrality. Eventually congress declared war on Germany in 1917. One year later the war ended in November 11, 1918. During WWII, again the U. S tried to stay neutral but still supplied the Allied cause. But the attack on Pearl Harbour on December 7, 1941 forced congress to declare war on Japan and Germany. And 4 years later the war ended in 1945. But the U. S heavily supplied the allies and when the time came with men.