If you're using BuddyPress, the registration fields are very easy to customize by using BuddyPress profile fields. Any profile fields you add using BuddyPress are automatically integrated in the Membership registration form.

Aside from using BuddyPress, a bit of custom work would be required to achieve that. If you're comfortable with coding, you can take a look at simple.invitecodes.php in membership/membershipincludes/plugins in the Membership plugin folder for a good way to get started.

If you're not quite so comfortable with coding, you may want to consider posting the request to the job board here on site.

Cheers,
Phil

Is it possible to add extra fields in the registration page? I want to include address fields, phone numbers and disclaimers into my set-up.

Could you please point me in the right direction?

I just became a premium member so that I can use this membership plugin.

Thanks.