If a game or app tells you that DirectX 11.1 is missing, first ensure your graphics card drivers are up to date. Manufacturers like NVIDIA, AMD, and Intel frequently release driver updates that include the necessary API hooks for DirectX 11.1. If the problem persists, use the "DirectX Diagnostic Tool" (type 'dxdiag' in your Windows search bar) to verify your current version and check for any hardware tab errors.
You already have it. No download is needed. However, if a game complains about missing d3d11.dll or similar, install the (which updates legacy DirectX 9–11 components). directx 11.1 download 64 bit