Your GPU needs to support DirectX 12, or DirectX 12 Ready Card.If your GPU supports it, then Windows Updates should automaticly install DirectX 12 capable driver.
Thanks Pumpkin Pie, I suspected something like that, although I would have thought that since beta versions of Windows 10 and DirectX 12 have been out for a while now, the big guys like AMD and Nvidia would have been able to create drivers/updates that implement DirectX 12 for GPUs which they are still selling. I hear DirectX 12 gives a significant boost to graphics performance.