Can you clarify-------are you referring to your primary account? If so, you can't delete it. It is your sign-in credential. Or do you mean a secondary account? Or an external account you added under "Add email accounts" in the folder pane? Something else?
Hi! It is an external email I added under "add mail account" in the folders pane
Right then. On the Inbox page click on the gear icon in the upper right corner, then on Settings. In the left pane of the landing page click on "Accounts". You should then see the account in question. Look to the right end of it for a small trashcan icon and click on that.