Why don't I have Directx 12 on Windows 10?

I downloaded windows 10 and check dxdiag and it showed I have I have directx 11.1 please help

Do you:

Have a DX12 compatible card?
If you have a card, do you have the drivers that supports DX 12?

Don't have a DX 12 card so I can't test it but that's the most logical thing that's happening.