You will receive a code that is redeemable for the cards from the deck listed above on the Pokemon TCG Live service. You will not receive any physical product mailed to you.
The PTCG Live game limits the number of codes that can be redeemed per account. There's a 4 code limit you can redeem for cards and a 1 code limit you can redeem for non-cards. Any additional codes you redeem give you Crystals instead of cards or Coins instead of accessories.
Upon purchase you will receive a separate email from firstname.lastname@example.org with all the codes ordered. This email may end up in your spam folder.