American options are those which can be exercised by the option holder at any time up to the expiration date.
Options vary in style: American options (American style) and European options (European style). The main difference between them is that they have different expiry conditions. Therefore, American options are more popular among investors since they provide better opportunities to exercise contracts when the have more attractive points and catch this moment without waiting for the expiration.
American options can be exercised anytime if necessary before its expiry date. For such options, execution is determined solely by the rules that are currently in force with respect to the underlying asset delivery dates, as well as the broker’s capabilities through which transactions are carried out in the market. There may also be restrictions on the number of contracts to be exercised during a trading day.