For managing a ticket template, you were given three options which are view, edit and delete.
Path: Space > Ellipse Icon > Settings > Ticket
Select your desired space to see the Ellipse Icon.
For managing the existing template ticket simply click on the ellipse icon on right of the box and click View to view the details.
Here you can view the template details.
To edit a ticket template, click the Edit option.
Now you can edit the template and click the Submit button..
For delete a ticket template, click on the Delete option.