Using the existing UCD Email Templates, you can easily modify emails according to the business requirement. 

Follow the below steps to modify the email templates:

1 - Go to the Setup menu.

2 - In the Quick Find Search box, enter Email Template and select Classic Email Templates.

3 - Then, in the Folder drop-down, Select Update Client Details Templates, and the managed Email Templates will appear. 

4 - Now, you can select the email template according to the requirement, for example, as shown below. Click on the Email Template Name

5 - It will look like the below image, then click on the Edit HTML Version.

6 - Now, please edit the template as it's required and click on the Save Button.

You'll then see the emails going as per the enhancements.