Despite being able to trade 24 hours a day, 5 days a week, you shouldn’t (Forex trading is not quite 24.7). You should only trade a forex pair when it’s active, and when you’ve got enough volume. Trading forex at weekends will see small volume. Take GBP/USD for example, there are specific hours where you have enough volatility to create profits that are likely to negate the bid price spread and commission costs.
A forex or currency futures contract is an agreement between two parties to deliver a set amount of currency at a set date, called the expiry, in the future. Futures contracts are traded on an exchange for set values of currency and with set expiry dates. Unlike a forward, the terms of a futures contract are non-negotiable. A profit is made on the difference between the prices the contract was bought and sold at. Most speculators don't hold futures contracts until expiration, as that would require they deliver/settle the currency the contract represents. Instead, speculators buy and sell the contracts prior to expiration, realizing their profits or losses on their transactions.
Forex is a portmanteau of foreign currency and exchange. Foreign exchange is the process of changing one currency into another currency for a variety of reasons, usually for commerce, trading, or tourism. According to a recent triennial report from the Bank for International Settlements (a global bank for national central banks), the average was more than $5.1 trillion in daily forex trading volume.