Editing Email Templates
Email templates are set up individually for each of your case types.
Open the Configuration Manager (normally found at your website address /config), open Case Management, then the case type you'd like to configure.
Email Categories
The "Email content" section lists all of the categories of email that can potentially be sent during a case.

Email Templates
Within each category the various versions of the email templates are shown.

Editing Templates
Each template can be edited, and the sending of the email can be toggled on/off.

There's more information about the tokens you can use in emails in the Case Management Emails, Templates and Tokens - Email and Task Title Tokens article.
Creating Templates in the Comms Manager documentation describes the allowed HTML elements and attributes. You can also add additional elements and attributes to the allowed list in your Environment Configuration.
GOV.UK Notify
By default, templates are written in HTML, like the image above, and are sent using the platform's Email worker. If you subscribe to the GOV.UK Notify service, and have purchased the GOSS GovNotify Connector (worker), you can switch your templates to use Notify instead. Notify is enabled in the Comms Template Manager - there are no additional settings in Case Management. The change is universal and all of your templates will have to be written using Markdown and go via GOV.UK Notify. See Creating Templates - Edit Variant - Markdown with GOV.UK Notify.
