: You can buy digital keys directly from the developers, which are typically redeemed via Steam. Humble Bundle
An activation key is a unique code that is used to activate a software product, in this case, Euro Truck Simulator 2. The key is used to verify the authenticity of the game and unlock its full features. Without a valid activation key, players can only play the game in demo mode, which has limited features. Euro Truck Simulator 2 1.40.4.8 Activation Key