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.
Strike Price: This is the price at which you could buy or sell the underlying futures contract. The strike price is the insurance price. Think of it this way: The difference between a current market price and the strike price is similar to the deductible in other forms of insurance. As an example, a December $3.50 corn call allows you to buy a December futures contract at $3.50 anytime before the option expires. Most traders do not convert options to futures positions; they close the option position before expiration.
For example: A trader in October 2016 agrees to deliver 10 tons of steel for INR 30,000 per ton in January 2017 which is currently trading at INR 29,000 per ton.  In this case, trade is assured because he got a buyer at an acceptable price and a buyer because knowing the cost of steel in advance reduces uncertainty in planning. In this case, if the actual price in January 2017 is INR 35,000 per ton, the buyer would be benefitted by INR 5,000 (INR 35000-INR 30,000). On the other hand, if the price of steel becomes INR 26,000 per ton then the trader would be benefitted by INR 4,000 (INR 30,000- INR 26000)
Covered calls can make you money when the stock price increases or stays pretty constant over the time of the option contract. However, you could lose money with this kind of trade if the stock price falls too much (but can actually still make money if it only falls a little bit). But by using this strategy, you are actually protecting your investment from decreases in share price while giving yourself the opportunity to make money while the stock price is flat. 
Options belong to the larger group of securities known as derivatives. A derivative's price is dependent on or derived from the price of something else. As an example, wine is a derivative of grapes ketchup is a derivative of tomatoes, and a stock option is a derivative of a stock. Options are derivatives of financial securities—their value depends on the price of some other asset. Examples of derivatives include calls, puts, futures, forwards, swaps, and mortgage-backed securities, among others.
Still other traders can make the mistake of thinking that cheaper is better. For options, this isn't necessarily true. The cheaper an option's premium is, the more "out of the money" the option typically is, which can be a riskier investment with less profit potential if it goes wrong. Buying "out of the money" call or put options means you want the underlying security to drastically change in value, which isn't always predictable. 
For example: Tomatoes are cheap in July and will be expensive in January, you can’t buy them in July and take delivery in January, since they will spoil before you can take advantage of January’s high prices. The July price will reflect tomato supply and demand in July. The forward price for January will reflect the market’s expectations of supply and demand in January. July tomatoes are effectively a different commodity from January tomatoes.
When buying or selling options, the investor or trader has the right to exercise that option at any point up until the expiration date - so simply buying or selling an option doesn't mean you actually have to exercise it at the buy/sell point. Because of this system, options are considered derivative securities - which means their price is derived from something else (in this case, from the value of assets like the market, securities or other underlying instruments). For this reason, options are often considered less risky than stocks (if used correctly).