Basic job descriptions can be found in your bylaws. More detailed descriptions for a bigger variety of positions can be found in the PTA ToolKit.
Every PTA is required to have, at a minimum:
Beyond that depends on the needs of your particular group. Additional Job Descriptions
Your bylaws will tell you what positions have been approved by your membership. If you want to create new positions you will need to update your bylaws and/or standing rules. For assistance in doing this, contact our parliamentarian at email@example.com.