Disclaimer I am not affiliated with any of the companies listed on this page, this is just for informational purposes only. However some links include a code that when used gives me commission.
Brokers are companies that buy the crypto on your behalf and send it to you. This makes the process easier but they charge a fee that is usually included in the price they charge for the crypto.
Exchanges are the market where buying and selling happens, you can likely get a better rate than on the broker but the buying process can be a little more complicated
International exchanges often have more volume for a better price and can often provide access to more coins/tokens, but you may have to wire your fiat funds internatioonally.