First, set up your primary registration. You can use any type of registration (simple, RSVP, ticketed, or multi-event).
Next, create a secondary registration form. To set up secondary registration, go to Setup > Registration > Advanced. Then, scroll down to Secondary Registration Pages and click Add/Manage.
This will prompt you to name your secondary registration and add a description (if desired). Once you save, the interface will look the same as your primary registration. Go to Setup > Registration to set up your secondary registration flow.
Your secondary registration will have a separate URL. You can edit the URL as needed, by clicking on Setup > Website > URL from your dashboard. To share the registration, either email the link directly or add to your website as a link or button.