Adding a player to friends by game ID is not currently supported, and the whole process is done by connecting the game to Facebook. Two things to be noted though:
- Both you and your friends are supposed to be connected to Facebook in War Robots and give permission to view friend list (when connecting to Facebook);
- Only those who are playing on the same platform (iOS/Android/Amazon) as you will be automatically displayed as friends in War Robots.
If both conditions are met, you'll see friends added in the Squad (level 10 required), Custom Game (level 10 required), and Leagues (level 5 required) menus.