Send Mail on Behalf of

If you want to send emails on behalf of an other email account you need to first configure it from your Gmail settings. Follow these steps:

1. Go to your gmail settings
2. With in the section "Send mail as:" click the "Add another email address" link
3. Follow the instructions to add your new account. More instructions here

Once the new account is added. Refresh the add-on and under 'Show Email Settings' you should find the option to choose from which email account you want to send the emails