The so-called free foreign exchange refers to foreign exchange that can be freely bought and sold in the international financial market, widely used in international settlement, internationally recognized and freely convertible into other countries' currencies.
Generally speaking, the subject matter of various foreign exchange can only be actually settled internationally after it is converted into deposit currency in the local bank deposit account of the currency issuing country, that is, cash exchange. All foreign paper money is not necessarily foreign exchange. Whether foreign paper money is called foreign exchange depends first on whether it can be freely exchanged, or whether it can be returned to other countries and deposited into the general account of any commercial bank in that country without restrictions. And you can transfer money at will when you need it, so it can be called foreign exchange.
In the foreign exchange quotations published by designated foreign exchange banks, the cash buying price is less than the cash buying price, while the cash selling price is equal. This shows that the country's foreign exchange management policy is to encourage the holding of cash and limit the holding of cash because cash is more convenient for foreign exchange management than cash.