EndTask

[DllImport("user32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)]
public static extern bool EndTask(
   IntPtr hWnd,
   [MarshalAs(UnmanagedType.Bool)] bool fShutDown,
   [MarshalAs(UnmanagedType.Bool)] bool fForce
);

Microsoft documentation: Link