Thanks for reaching out in the Community about this.
Just to double-check, were you not able to see at all the option to pick a display name when you created your Spotify account?
If that's the case, can you try creating a new account again while using your browser in incognito mode and let us know whether you have the same issue?
Alternatively, if you were able to pick a display name when creating your account but you can't see it, you can check this Ongoing Issue and make sure to click +VOTE as well as to stay up to date with its development.
Please keep us posted and let us know if we can help with anything else as well!
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