Stormbloodit is now available for free until the eighth maggio expansion of Final Fantasy 14.
"The digital version of Final Fantasy 14: Stormblood will be available to game owners and new purchasers of the Final Fantasy 14 Online Starter Edition, which includes A Realm Reborn and the first expansion, Heavensward," according to a press release.
Final Fantasy 14 Online is now available for both new and existing players, thanks to Square Enix. Of course, a valid subscription is required to play the game.
Final Fantasy 14 isn't available for free in the PC version, nor are it available on Steam. Also, the PC version and the Steam version of Final Fantasy 14 are "treated as separate platforms," so you'll need to launch the client and download Stormblood; you can't access your Steam account via the Windows client or vice versa.
Final Fantasy 14's Stormblood expansion is also available for PS4 and PS5: go to the PlayStation Store and get this additional content.
Final information on patch 6.4: release date and first information from Square Enix