How do you delete your account here?
This forum uses Discourse software, which means the rules about things like that are not set by us. In Discourse, users can’t delete their accounts (unless their accounts are less than a few days old and have made at most one post).
Users can tell a moderator to delete it, or tell a moderator to “anonymize” it. Anonymizing an account changes the username and password so nobody can ever impersonate you or steal your inactive account. Be warned that this includes you if you someday change your mind, but it keeps the posts around so the forum is readable.
Another option is that if the problem is receiving e-mails you don’t want, you can “Unsubscribe” yourself from those.