By default the End User Features is disabled. However, you can enable it with one click. Due to its complexity, the EUF feature requires a separate license (free). But before you proceed with any steps in this KB, you must have an active cPanel Varnish Plugin license. Be sure to sign up for one before proceeding further with this KB!
So the first step you need to take is to head out to this product page to get the license key. Once you've received the key, copy/paste it into WHM -> UNIXy.Net Varnish Plugin -> End User Features -> License. Then hit the Go button to fully enable EUF.