Account items such as content packs, PLEX and items purchased through the New Eden Store, are delivered to the account’s Redeeming System. These items can be redeemed by accessing the "Redeemable Items" screen, accessible from the bottom of the character selection page.
Alternatively, they can be redeemed through the Gift Box icon at the bottom of the Neocom, which will show if there are any items to redeem.
Finally, the shortcut "ALT-Y" can be used to open the redeemable items screen.