You can set up Email Notifications in the Settings section of the app - Accesible from the top-right menu.
On Activation, It will request your email address if you have not yet entered it. Now, every time an order is filled, you will receive an email with the details.
To Deactivate, go to Settings and switch off Email Notification.
To Edit the email address, go to Settings and click on Email Notifications Arrow to see and edit your address.