Click that and read the first comment posted under the question.
If it helps, a C++/CLI project with just #include <windows.h> int main() {POINT p; GetCursorPos(&p);} gives me linker errors, but adding #pragma comment(lib, "user32.lib") below the include links it all properly. I reckon you didn't add the library to the project properly.
I do not know what to add. Because getcursorpos is in the windows.h library.
windows.h isn't a library, it's a header file. You should learn the difference, because you're going to have a tough time understanding compiler and linker errors without understanding that.
There is loads of documentation for the standard MS/Windows libraries, so it should be easy to find out where that function is defined; indeed, it looks like other posters in this thread have already been able to find that information for you.