Options on futures began trading in 1983. Today, puts and calls on agricultural, metal, and financial (foreign currency, interest-rate and stock index) futures are traded by open outcry in designated pits. These options pits are usually located near those where the underlying futures trade. Many of the features that apply to stock options apply to futures options.
Conversely, a put option is a contract that gives the investor the right to sell a certain amount of shares (again, typically 100 per contract) of a certain security or commodity at a specified price over a certain amount of time. Just like call options, a put option allows the trader the right (but not obligation) to sell a security by the contract's expiration date.
As an example, let's say an initial margin amount of $3,700 allows an investor to enter into a futures contract for 1,000 barrels of oil valued at $45,000—with oil priced at $45 per barrel. If the price of oil is trading at $60 at the contract's expiry, the investor has a $15 gain or a $15,000 profit. The trades would settle through the investor's brokerage account crediting the net difference of the two contracts. Most futures contracts will be cash settled, but some contracts will settle with the delivery of the underlying asset to a centralized processing warehouse.
If in six months the market crashes by 20% (500 points on the index), he or she has made 250 points by being able to sell the index at $2250 when it is trading at $2000—a combined loss of just 10%. In fact, even if the market drops to zero, the loss would only be 10% if this put option is held. Again, purchasing the option will carry a cost (the premium), and if the market doesn’t drop during that period, the maximum loss on the option is just the premium spent.
The price at which you agree to buy the underlying security via the option is called the "strike price," and the fee you pay for buying that option contract is called the "premium." When determining the strike price, you are betting that the asset (typically a stock) will go up or down in price. The price you are paying for that bet is the premium, which is a percentage of the value of that asset.