Our preview URL feature utilises a web proxy that allows you to view your site on a different URL to what you have set up in your control panel. This means you preview the site on the preview URL whilst having the site itself set up using the live URL in your hosting. The benefit of this is that you then don't have to make any underlying changes to the site when it's time to put it live as using of the preview URL makes no changes to the underlying site. This means that no action is required when putting a site live.
So when you are ready to go live, simply change the DNS for the domain to point at the server on which you have set up the website.
Please see our guide on how to point your DNS here:
We also have a more in depth guide on how the preview URL works here: