What is meant by the exchange rate, fixed exchange rate, flexible of fixed exchange rate?

Exchange rates – They link national currencies for purposes of international trade. There are broadly two kinds of exchange rates: fixed exchange rate and floating exchange rate.
Fixed exchange rates – When exchange rates are fixed and governments intervene to prevent movements in them.
Flexible or floating exchange rates – These rates fluctuate depending on demand and supply of currencies in foreign exchange markets, in principle without interference by governments.