1
Tap Settings (the gear icon at the top of the screen).
2
Tap the Link button in the top right corner of the screen.
3
Tap the Call of Duty button from the options provided.
4
Once the browser opens, enter your email address and password and tap Login Now.
Cross-platform and available now, download Warzone to jump into a match, completely free. Download Warzone, then link your Call of Duty account to Call of Duty: Mobile and you'll have some new Modern Warfare gear an in-game watch waiting in your Modern Warfare inventory.