What is the best way to exchange money without fees?

I'm curious about the most cost-effective method for exchanging money without any fees. With the rise of cryptocurrencies and digital payment methods, there seem to be numerous options available. Could you elaborate on which platforms or techniques offer the most favorable rates without any additional charges? Additionally, I'm interested in knowing if there are any hidden costs or caveats I should be aware of before making such a transaction. My goal is to ensure a smooth and efficient exchange process without incurring any unnecessary expenses.