In 1502, we are planning for more flexibility where the end user can choose the form he/she wants to preview/generate. Today, the end user can only preview/generate the form that ships out of box. So your options for now are:
1. Edit the existing forms we have provided
2. Create a new form(s) and then create a custom button for the end user to preview/generate the custom form(s) or the tenant to automatically generate the form and attach it to the Ticket via custom Action/Batch Job
3. Wait for this new feature planned for 1502
