There seem to be several ways of doing it in Win32 environment, using interfaces such as ManagementObjectSearcher. However, I am unable to find a way to achieve it in UWP. There is nothing akin to Graphics Card Adapter in Device Interface Classes either.
I couldn't find any MSDN documentation on this topic.
Check out the list of supported Win32 APIs in UWP: https://msdn.microsoft.com/en-us/library/windows/apps/mt644397.aspx
It contains the IDXGIFactory interface, which has the EnumAdapters method: https://msdn.microsoft.com/en-us/library/windows/apps/bb174538.aspx