Blizzard has announced the details of the launch of Diablo Immortal on PC and mobile systems, revealing that the PC version is currently preloaded from Battle.net by anyone who does not want to wait to play on launch day, which is June 2, 2022.
We can therefore read that Starting today, you can pre-load Diablo Immortal on PC via Battle.net. Warm-up your PC in advance, so when Immortal releases on June 2nd, you can throw open the gates of the Underworld and slay demons without beating around the bush!
To preload the game, start from this page, where you will be guided through the procedure and, if necessary, to download Battle.net, Blizzard’s proprietary client. Of course, in order to take advantage of the preload, you must have an active and unrestricted Battle.net account. You can create one by clicking here.
In the same post, Blizzard also explained how to set up cross-play, so you can transfer game progress from mobile to PC:
A Battle.net account is required to play Diablo Immortal on both PC and mobile without compromise. You can play with a guest account and later log in or create a Battle.net account to transfer your progress to your PC. Please note: Guest accounts are only accessible on the device on which they are created unless cloud backup has been activated.