Whether you have just created a new locale or want to edit the defaults, you will follow the same general instructions. In addition to basic html and text content, you can use a number of predefined variables to populate the e-mails with information from the database.
To edit content of a template:
Note: All contacts are set to receive HTML by default when they come through the online store. If you do not want a specific customer to receive HTML e-mails, go to the customer's account details page and click Edit primary. Uncheck HTML for the E-mail Format. Click Edit contact.
Caution: This will replace this existing template. Please make a backup of your existing template if you do not wish to lose it.