Where is the inflation from / What causes today's inflation?

Milton Friedman once said inflation is everywhere a monetary phenomenon. Thereafter I can ask the question: how we got this kind of monetary phenomenon today, which looks horrible to almost everyone? Or what causes the monetary phenomenon which shows up as today's inflation over every important economy?

I always thought China is a big contributor. Nobody except Rogoff mentioned in a article, thought China was actually exporting inflation. China exports cheap stuff, of course. But China also holds huge foreign reserve. Under normal conditions, the price keeps going down. But the foreign reserve stays in the economies which import the goods made in China. More they import, much foreign reserve they face. It cause the price of capital goods going up because billions need being invested. Then, after a break point, the Price Level is going up, instead of going down.

That is what happening now generally.

(I am going to build a model to estimate this in the future, if I get enough spare time.)