Approximately 12.2 GB to 17.3 GB , depending on selective components (compared to the original ~48 GB).
Windows 10 x64 (specifically build 1709, 1909, or higher) is mandatory because it is a UWP application. Installation & Troubleshooting Guide Approximately 12
Are you having during the installation process? Buy Halo Wars 2 | Xbox Approximately 12.2 GB to 17.3 GB
Release notes for this version typically include the following "paper" or set of instructions to ensure the game functions: Approximately 12