A common question is how to delete Warzone games.
Multi-player Warzone games can be deleted by the game creator when they're still in the lobby (i.e. when not all players have accepted the game yet.)
Once a multi-player game has begun, it cannot be deleted. If a game's players don't wish to finish the game, they can click vote to end under the Players button to prematurely end the game without declaring a winner.
If you're tired of seeing finished games on your My Games page, you can set your filter to only show you active games, or even to only show you games where it's your turn. By doing this, you no longer have to look at finished games in your list. See usability tips for more information.
Single-player games only live in your browser. Therefore, games are deleted simply when the browser is closed. If the game has been saved via the Saved Games tab, it can be deleted simply by visiting the Saved Games tab and clicking the Delete button.