In Blackjack, you try to get a hand closer to 21, without busting, than the dealer. Folding and Doubling Down are allowed only after the initial deal.
Doubling Down doubles your bet and you are dealt one and only one card.
Folding returns half your bet.
Blackjack on the deals doubles your winnings.
The dealer must draw on a soft 16 and stand on a soft 17 or higher.