In, At, or Out of the Money: If an option is in the money, its premium will have additional value because the option is already in profit, and the profit will be immediately available to the buyer of the option. If an option is at the money, or out of the money, its premium will not have any additional value because the options are not yet in profit.
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.
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).