Jay has backed up his iPhone and installed the iOS 10 Beta. He's having issues with iCloud sync with his iPad and Mac, along with the universal clipboard. Leo says that a beta version will always have some things that don't work. Leo suggests restarting everything to see if they sync back together. He also should make sure everything is updated to the latest version. Being on the same Wi-Fi network also helps.
One user says he'll have to have Bluetooth turned on as well. It could be that it uses Bluetooth to sync. iOS 10 will be finalized and released in a few weeks, along with OS X Sierra. It should clear up by then.