I think every country prints its own fiat currency according to their policies; generally this currency is printed and controlled by the country's central bank. After the economic revolution paper money was accompanied by credit, plastic money, etc. The latest form of digital money (bitcoin) was introduced in 2009. The purpose of all forms of money is to make trading simple and easy.
Anything that is easy to use as a medium of exchange in finishing a trade is called money. Commodities previously demanded such as salt, wheat rice, weapons, livestock are used as money, they are called barter exchanges. After that coins like gold, silver, copper became there. They are very popular. Soon this money was found uncomfortable and dangerous to carry, so it was replaced with paper currency.