DirectX11 is the current generation of DirectX technology. By default, Windows 7 includes DirectX11. So, there is no need to download DirectX 11 for Windows 7 64-bit. However, you may need to update it if you use another Windows version.
You may download DirectX 11 from microsoft.com or any other software archive. Additionally, you can download DirectX11 from our mirror host.
It will be interesting to see weather Windows 7 will support DirectX 12 in the future or not or if it will be a Windows 8 exclusive DirectX version.