To activate on PC, you primarily use a digital activation key through the Ubisoft Connect launcher. While the game is available on multiple storefronts, most keys—regardless of where they are purchased—must eventually be linked to a Ubisoft account to play. Where to Purchase Activation Keys
If you already own a key but cannot activate it, reach out to the game’s fan communities—Reddit’s r/Avatar and the Avatar Forums maintain updated guides for legacy activation. Avatar Pc Game Activation Key