On every new character you make on this account, they'll spawn with 'em in your bags.
Can't trade them, so if you started a character before entering the code, you won't see them unless you reroll.
They're not that useful in this day and age; all promotional items work from rank 1 to 10 which goes by so fast these days.
FFXIV: Cloe Delisle
Scholar, officer of the SWAGGER Free company, Sargatanas server.