To create a new message template, go to Notifications > Message Templates and click "Create New" button. Fill in all the required information. However, note that changing text color in the HTML message editor doesn't currently work.
Release: 17.4.2 and 17.4.3.0
Components: CA Service Desk Manager
The issue occurred in versions 17.4.2 and 17.4.3, but it's fixed in 17.4.4.0, as shown below. We recommend upgrading to 17.4.4.0.