I understand M-C-M as the way of capitalism to increase the profit every time money flows in society.

M= stands for money which is the initial investment, used to make purchases such as raw materials, labor and what is needed for production

C= Stands for commodities these are transformed into goods and services that hold value

M= Stands for money but this time (more money) after the profit gotten from the commodities, there must be a profit to meet this one

this way companies and employees keep growing their wealth as inflation keeps going up, but sometimes inflation is rising faster than the growth of money it self