Total war can be defined as war in which all parts of a society need to be mobilized and there is little difference between civilian and combatant. Many technologies helped bring total war about. Three of the most important were the tank, the truck, and the airplane.
All three of these technologies helped make war industrial. They helped to ensure that whichever side could manufacture more and better weapons would win. This made it necessary to mobilize a society’s whole resource base (with things like rationing of consumer goods) to win. The airplane, in particular, brought war to more people. The “strategic bombing” of WWII meant that almost any person in the countries where the war was happening could be a target at any time.