https://wccftech.com/download-ios-12-beta-for-iphone-ipad-ipod-touch/

Developers can now download iOS 12 Beta 1 for iPhone, iPad and iPod touch right now. Please make sure your device is compatible before going ahead.

After going through all of its features one by one on stage by Apple, developers can now finally download iOS 12 Beta onto their devices to test out themselves. If you are interested, you can read about all the feature additions here.