Once you reach Semi-Grade 2 in Type Soul, you will be able to redeem codes. Along the UI options at the top of your screen, ...

Afterwards, open the in-game menu and select ‘Link Play’ at the bottom, then ‘Mystery Gift’. Here, you can instantly claim ...

Codes for Anime Eternal mostly yield Potion Bundles, or at least that's what I've seen so far. That may leave you longing for ...