DirectX 12 is on Windows 8.1. While it is the standard for modern gaming on Windows 10 and 11, Microsoft never released a standalone DirectX 12 update or download package for the Windows 8.1 operating system. Compatibility Overview
If you have a game that requires DirectX 12 (Level 12_0 or higher), you have two primary options: directx-12-download-windows-8-1-64-bit
Even if you have a modern GPU (like an NVIDIA RTX or AMD Radeon RX series) that is "DirectX 12 Ready," it still requires a compatible to utilize those features. On Windows 8.1, your powerful graphics card will be restricted to DirectX 11.2 functionality. DirectX 12 is on Windows 8