Most foreign exchange companies are market makers. When making a transaction, there must be a counterparty, and if you buy it, someone will sell it. Market-making foreign exchange companies are counterparties who directly trade with you, so if you make money, the foreign exchange companies will lose money, and if you lose money, you will make money (here you will ask whether the foreign exchange companies will lose money, in fact, most customers will lose money). In this case, there is generally no commission, only the spread.
There is also a foreign exchange company called ECN. Your counterparty is not a foreign exchange company, but a bank. Foreign exchange companies only provide one quotation channel. So they will charge a certain commission for your transaction and make money from it. The spread is earned by the bank. So this situation has a commission, which is a bit bad. (The price difference is much smaller than the last one)
Another situation is that the foreign exchange company you are looking for is a platform agent and does not provide foreign exchange trading itself. Just be a nurse and introduce you to foreign big foreign exchange platforms. After all their hard work, they have to earn some money from you. This commission is in addition to the cost spread or commission charged by the normal platform. Because they are just agents, that is, advertising, so they don't take risks when foreign exchange companies close down or something, that should be said. This situation is a bit bad. It depends on whether the agent you are looking for is black.