Take an extra card or stop in Blackjack 21?

The player receives his two cards, he has the right to take an additional card and increase their total value of the hand, or not take cards and play with only two cards that were dealt after the deal

After the player receives his two cards, he has the right to take an additional card and increase their total value of the hand, or not take cards and play with only two cards that were dealt after the deal.
The player draws additional cards until he collects 21 points and wins, or 22 or more and automatically loses.

Doubling

This option allows the player to double their original stake in exchange for being able to receive only one additional card. For example, the dealer's face up card is 4, you have 3 and 6, which brings you a total of 9 points. This is the perfect situation for doubling. You increase your bet and hope for a 10-point card that will give you 19 points. The dealer can very easily go over or stop at 17. Either way, you win.

Separation

Splitting also allows you to increase your stake after the initial hand. If you have paired cards in your hand, you can split them into two hands. You will need to double your original bet to cover the second hand. Each hand will be played separately. A good pair to split is 8's. Two 8s give you a total of 16 points, so if you split them you have a chance of getting 10, which will bring 18 points and most likely win.