Currently, it's not possible to display multiple forms for a single request type when creating a ticket in the customer portal.

Suggestion

It would be great if we can add multiple forms to a single request type to be displayed during the ticket creation in the customer portal.

Workaround

Set up Automation to add a Form after Issue Creation. This means the Issue must be created first, but it will allow filling out the 2nd or 3rd, etc Form by the customer.