Since the game doesn't have an internal console, developers in the modding community created external tools to "inject" a console into the game process.
Once enabled, here are the most useful and safe commands for MW3. how to enable console in call of duty modern warfare 3
Right-click config.cfg and open it with (or Notepad++ if you have it). Since the game doesn't have an internal console,
: Offline "trainers" are often used to enable cheats (God Mode, Infinite Ammo) in Single Player since standard console commands like do not work. how to enable console in call of duty modern warfare 3