Open the Steam client, click the "Games" menu at the top, and select Activate a Product on Steam.... Enter your key there.
The 1.35.1.31 update was a significant patch released in late 2019 that introduced several major features: Euro Truck Simulator 2 Product Key 1.35.1.31
Significant visual and layout improvements to the German map region. Open the Steam client, click the "Games" menu
Added voice prompts in 9 different languages with male and female options. Open the Steam client
Added Sardinia (for Italia DLC owners) and new French roads for those with the Vive la France! DLC. How to Activate Your Game