: You can purchase the expansion directly on Steam for $19.99. It is also available as part of the Call of Duty Warchest bundle, which includes the original game and Call of Duty 2 .
To safely download and run the game's .exe files ( CoDUOSP.exe for single-player and CoDUOMP.exe for multiplayer), it is recommended to use official digital storefronts: download-call-duty-united-offensive-the-games-download-exe
: The game is available for PC through the Xbox Store , often bundled with the base game. : You can purchase the expansion directly on Steam for $19