NB: The account you used to post this question was created yesterday, and already has a display name.
The article you've linked to was posted almost three years ago, from
a different account[
^] which was created almost 4½ years ago.
You won't be able to change the details of the account that posted the article unless you log in as that account.
If you can no longer remember the password to that account, you can request a password reset.
Submit an article or tip