You don’t download DirectX 12 separately. Keep Windows updated, and you already have it. For older DirectX runtimes (9/10/11), use the Microsoft link above.
If you need a technical reference:
If you are getting errors about missing .dll files (like d3dx9_43.dll ), you may need the DirectX End-User Runtime Web Installer from . This does not install DirectX 12, but it provides older legacy libraries (DirectX 9, 10, and 11) that many games still require to run alongside the newer version. How To Update DirectX 12 The Proper Way On Windows windows directx 12 download