Every state has different forms/documents and profiles. There should be a date on the form with a label/prompt: IEP Effective From. The template checks the student's birth date against this date and must be at least 18 years old for the Student row to appear on the IEP Meeting Participants section of the IEP.
If the student is below 18 years old it will not auto populate the student into the Transition IEP Document. If this is not the state requirement anymore(e.g. maybe it's 14 now), we recommend reaching out to your district's Designated Support Contact, who should be able to connect with our PowerSchool Support team on your behalf to assist you further in this regards.