https://wccftech.com/download-ios-12-1-beta-without-developer-account-on-iphone-ipad-ipod-touch/

If you want to download and install iOS 12.1 beta on your iPhone, iPad or iPod touch right now before the public beta arrives then here’s how you can do it.

Apple has released the first ever beta of iOS 12.1 to registered developers a while back and anyone with an Apple Developer Program membership and a compatible device can go ahead and install it. But of course, if you don’t have a membership, it’s highly likely that the beta will be seeded to Beta Software Program (public beta) members in due course.