You cannot customize the default pages of an appointment using Microsoft Office Outlook form pages customizations. However, you can customize the first page of an appointment by by adding an adjoining form region. You can also use form regions to replace existing form pages. Learn more about form regions.
You can hide the default pages that cannot be customized. However, because these pages provide much of the Outlook appointment scheduling, it is recommended that instead of hiding them, you create new pages with additional functionality. You can also use form regions to customize the default pages by using the page control.
Meeting Request forms are not designed to be customized. Instead, customize an appointment form. The custom form is used when the appointment is converted to a meeting.