1. Delete your email account from the Mail app

1. Open the Mail app, then on the left pane, right-click on the email account that you will want to remove from the Mail app.
2. After this, click on the option Account settings.
   
3. While the Account setting page is open, click on the option Delete account from this device.
4. Now, you will receive a confirmation message.
5. Click on the Delete button, in order to remove the account from the Windows 10 Mail App.
6. After the process is complete, a message will appear saying Your account has been successfully deleted.