Who declared a national holiday in 1938 this holiday was dedicated to remembering veterans

Answer: The National holiday was known as "Armistice Day", declared a federal holiday after a Congress resolution.

Explanation:

The holiday was declared on November eleventh, the same day WWI ended, and it was meant to honor both world peace and the veterans who had fought in the conflict. After WWII, in 1954, Eisenhower changed its name to "Veterans Day", focused on honoring American veterans.