If you want to add your account into Akasha then all you need to do is make sure to go to your profile settings in-game and turn on "Show character details", otherwise the website won't be able to see it.

Genshin showcases are not updated immediately which means you might have to wait few minutes (at most 5 minutes) before attempting to load your profile (as well as when updating it with new artifacts etc)

If the account was already looked up on the website before then you can use in-game nickname to find it. Otherwise you have to use account UID or Enka.Network's profile name.