If you've added custom form questions and they are not appearing on the first page of your registration, it may be for two reasons:
you're collecting no/not attending RSVPs, or
you're using RSVP Registration.
By default, the system only asks custom questions of those who are attending or who have confirmed that they can RSVP.
The way to show all registration questions on the first page is to not collect no/not attending RSVPs and to use Ticketed or Simple Registration.