DarknessShallFall wrote: »"Upgrading to Morrowind
Everyone who logs into ESO who has not yet upgraded to Morrowind will see a registration screen that will notify you that Morrowind is available, and will give you instructions for upgrading the base game to Morrowind via a simple digital upgrade purchase. This screen is also the main interface for entering retail Morrowind codes – anyone who has purchased Morrowind new at retail (starting June 6) will use this screen to register their purchase by entering the code included in their physical retail box."
Also they would most likely be in your e-mail.