Use Setup -> Email templates to adjust email templates that are sent from the system. These are both: system notifications to employees and automated responses to customers.
As an example, let's choose email template New ticket opened (opened by staff, send to customer).
You will see a list of formulas that are used in the template and which field they represent.
Instead of formulas placed in a template, system will put related information accordingly, when a template is sent to customer.
Modify text or formulas in the template according to your vision and save changes:
This way you can update all other templates.