Suppose you enter a futures contract to buy one lot of USD/EUR at 0.8400 (purchase $100,000 for €84,000) in a year. You may, perhaps, be selling in the Eurozone and want to repatriate your profits in one year. A futures contract removes the risk of a possible appreciation in the U.S. dollar against the euro and helps you better plan your finances. In this case, if the US dollar appreciates, each euro will purchase fewer dollars when repatriating the funds.
If the US dollar appreciates and USD/EUR is at 1.0000 in a year, without a futures contract, the spot rate would be $100,000 for €100,000. However, instead of this rate, you would enter the previously agreed-upon contract of one lot of USD/EUR at 0.8400 ($100,000 for €84,000). In this simple example, you will have saved on a cost of €16,000 per lot, not considering any fees.