Account deletion can only be done by an Admin. Deleted accounts are not recoverable and the content can't be recovered.
If for some reason, you need to delete your team's Tettra account, you can do so through three easy steps.
Scroll to the bottom of the Admin settings page and click Delete this account.
On the confirmation page, you may choose to export your data or proceed to deletion by entering your team's name. Once done, click Delete account. Your account deletion should be processed within a few minutes.