Adding an email template can be done in two ways:
1.1 Go to 'user'
1.2 Click 'Email templates'
1.3 Create email template and hit 'save'. Within few minutes the templates will be available on all your devices.
2) In App
2.1 In the actions menu, click 'Mail'
2.2 Create the email you would like to save as an template and hit 'Save as template'.