To remove an e-mail account from Canary on macOS, please follow the below mentioned steps:
1) In the system menu bar, click the Canary Mail menu.
2) Click Preferences.
3) Click the Accounts tab to display all e-mail accounts added to Canary.
4) Select the account you wish to delete.
5) Click the Delete icon shown below.
6) Click Continue to finalize the action. You account and all its associated data will be deleted from Canary. This cannot be undone.
