Option contract is a kind of contract that gives both parties the right to buy or sell a related tool or asset at a certain price-exercise price or exercise price-before or after the future maturity date, but it is not an obligation. The price that the buyer of the option contract pays to the seller to obtain this right is called option fee. An option contract is a contract about the right to buy and sell a specific commodity at a certain price in the future. The underlying assets of options include: stocks, stock indexes, foreign exchange, debt instruments, commodities and futures contracts. There are two basic types of options, call option and put option, also known as call option and put option. The holder of a call option has the right to buy the underlying assets at a specific time and at a specific price. The holder of a put option has the right to sell the underlying assets at a specific time and at a specific price. The price in option contracts is called the strike price or strike price. The date in this contract is the expiration date, execution date or expiration date. American options can be exercised at any time during the validity period of the options. European options can only be exercised on the expiration date. Most options traded on exchanges are American options. However, European options are usually easier to analyze than American options, and some properties of American options can always be deduced from the properties of European options.