In contrast to buying options, selling stock options does come with an obligation - the obligation to sell the underlying equity to a buyer if that buyer decides to exercise the option and you are "assigned" the exercise obligation. "Selling" options is often referred to as "writing" options.
When you sell (or "write") a Call - you are selling a buyer the right to purchase stock from you at a specified strike price for a specified period of time, regardless of how high the market price of the stock may climb.
One of the most popular call writing strategies is known as a covered call. In a covered call, you are selling the right to buy an equity that you own. If a buyer decides to exercise his or her option to buy the underlying equity, you are obligated to sell to them at the strike price - whether the strike price is higher or lower than your original cost of the equity. Sometimes an investor may buy an equity and simultaneously sell (or write) a call on the equity. This is referred to as a "buy-write."