When you enable the URL section, you can customize the Calendar Reminder, Email Notification, and Social Sharing Registration links.

To Add a webinar to your calendar, the registration URL will point to your third-party registration page.

You can customize the emails that get sent out to your audience. The Webinar's Audience URL variable ${webinar.link} will point to your third-party registration page.

The Social Sharing component allows attendees to share your webinar with their colleagues on all major social media platforms. The registration URL will point to your third-party registration page.