import QtQuick 2.9
import QtQuick.Window 2.2

Window {
    visible: true
    width: text1.width
    height: text1.height
    title: qsTr("Hello World")
    flags: Qt.FramelessWindowHint
    color: "#70000000"
    x: 0
    y: 0
    Text {
        id: text1
        x: 0
        y: 0
        text: "Hello World"
        color: "#FFFF0000"
    }
}

int main(int argc, char *argv[])
{
    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
    QGuiApplication app(argc, argv);
    QQuickView::setSceneGraphBackend(QSGRendererInterface::Software);
    QQmlApplicationEngine engine;
    engine.load(QUrl(QStringLiteral("qrc:/main.qml")));

    if (engine.rootObjects().isEmpty())
        return -1;
    QQuickWindow *pMainWnd = qobject_cast<QQuickWindow*>(engine.rootObjects()[0]);
    HWND hShowWnd = (HWND)pMainWnd->winId();

    DWORD dwStyle = GetWindowLong(hShowWnd, GWL_STYLE);
    SetWindowLong(hShowWnd, GWL_STYLE, dwStyle | WS_POPUP | WS_VISIBLE);
    DWORD dwExStyle = GetWindowLong(hShowWnd, GWL_EXSTYLE);
    SetWindowLong(hShowWnd, GWL_EXSTYLE, dwExStyle | WS_EX_TOOLWINDOW);
    HWND hWndParent = FindWindow(nullptr, TEXT("MFCApplication1"));
    SetParent(hShowWnd, hWndParent); //Windows API
    return app.exec();
}

it can not display on MFCApplication1 Window