Its not necesraily one person who "invented it", however, the idea of it came about at the beginning of World War I from the writings of Carl von Clausewitz, Helmuth Karl Bernhard Graf von Moltke, and Alfred Von Schlieffen (these were all German War Strategists) who heavily favored extreme maneuverability and speed on a massive scale. While this seems pretty common knowledge and ideal today, back when this strategy was first proposed, this was seen as way too risky (keep in mind they had the "old school" mindset of what war is). This idea in WW1 was more common at the beginning of World War I on the eastern front; when the Germans and Russia kept trying to out maneuver each other (obviously this was done on foot, so it was near impossible, even with deception, to perform this given the technology at the time).

As to who came up with the word "Blitzkrieg" and the strategy as we know it in World War II, is mostly credited to Heinz Guderian