If you look at the MSDN documentation for SmbiosInformation Class you'll see it's part of the "Windows Desktop Extension SDK" which means it's not defined by default in a project.
You need to add a reference to the Windows Desktop Extension SDK to your application. For a Visual C++ project using C++/CX, you'd add it by using Add a Reference... to Universal Windows -> Extensions -> Windows Desktop Extensions for the UWP (pick the version that matches the Target OS version you are using for your project). See MSDN
NOTE: If you were using C++/WinRT language projections instead of C++/CX, it's all inline in the header
winrt/Windows.System.Profile.SystemManufacturers.h including the known GUID values as
constexpr values so you don't need to link with anything special.
Note that if your application supports anything besides just the Desktop device family, you should guard you use of that class for runtime failure or by checking for support of the
Most applications that attempt to use this API will get
E_ACCESSDENIED. Only special applications listed by the system manufacturer in the system configuration are allowed to use this particular class. See this post for what this is all about.