Currency trading and exchange is fairly intuitive. When you go to visit another country, you need to have the currency of that country since your own money won’t work. The rates of this money exchange aren’t decided by governments however though they can influence them to some degree. But there isn’t a really a way to fix the price of any given currency. Traders in foreign currency decide those rates for a lot of currencies as they’re constantly in exchange of them all around the clock trading more than trillions of dollars’ worth and the price will change a lot of very common currencies like what currency is used in Italy.
That would be Euro, though it used to be Lira for Italy. When getting your money exchanged in a foreign country, it’s entirely possible to be scammed by a stranger offering lucrative rates to you. They might be using counterfeit money of their own to get your real foreign money and you won’t be any wiser to it. If you try to use counterfeit money, you have a good chance of getting arrested and you’re the one who has to suffer persecution. Always try to plan for these money exchange trades.
Even if it isn’t a scam, some money exchangers take such a large cut that you might as well feel like it was. The bank might have a better exchange rate and if you can, it’s better to go to them. In fact, if you can hold off your money exchange until you’re actually in the country you need the currency of, you can probably get a better rate than at a money exchange or bank back home. This isn’t universal however, changing currencies is very volatile and depends a lot on the position of that country.