MsiGetTargetPath

[DllImport("msi.dll", CharSet = CharSet.Auto)]
public static extern int MsiGetTargetPath(
   [MarshalAs(UnmanagedType.LPTStr)] string szProduct,
   [MarshalAs(UnmanagedType.LPTStr)] string szFeature,
   [MarshalAs(UnmanagedType.LPTStr)] StringBuilder szPathBuf,
   ref int pcchBuf
);

Microsoft documentation: Link