Google now let you create and manage your URL channels under the My ads tab in new AdSense interface. "Since you already manage your custom channels from the My ads tab, we hope this move will provide a more consistent experience when managing all of your channels," Google said.
At the same time, you can continue to view the performance of your various channels under the Performance reports tab.
"URL channels allow you to track earnings for your domains, subdomains or pages. With this change it's possible to create URL channels for AdSense for content, games, video, mobile AdSense for content, and AdSense for hosted content in the new interface. You can also remove or deactivate channels that you're no longer using. Learn more about URL channels," Google stated.
Also, note that with the recent launch of the Sites report, you can now see your domain and subdomain earnings without the need to set up URL channels. For tracking page level data or any other grouping of pages.