SE has announced that:

I bought FINAL FANTASY XIV: A Realm Reborn online but am yet to receive my registration codes. Where are they?

If you purchased FINAL FANTASY XIV: A Realm Reborn from the Square Enix Store, your registration codes for the full version of the game will be sent out on the morning of launch day, August 27th.
If you purchased from another online retailer, please contact them for more information on your specific order.
http://support.eu.square-enix.com/fa...68510&ret=main