multiple subwindow with same widget QMdiSubwindow

i want to change object in all my subwindows this is my code

import sys
from PyQt5.QtWidgets import *
from PyQt5 import QtWidgets

class MainWindow(QtWidgets.QMainWindow):
    count = 0
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.mdi = QMdiArea()
        self.setCentralWidget(self.mdi)
        bar = self.menuBar()

        file = bar.addMenu("Subwindow")
        file.addAction("New")
        file.addAction("Change Text")
        file.triggered[QAction].connect(self.click)
        self.setWindowTitle("Multiple window using MDI")

    def click(self,action):
        print("New sub window")
        if action.text() == "New":
            MainWindow.count = MainWindow.count + 1
            sub = QMdiSubWindow()
            sub.setWidget(QTextEdit())
            sub.setWindowTitle("subwindow" + str(MainWindow.count))
            self.subwindow = self.mdi.addSubWindow(sub)
            self.subwindow.show()
            self.label3 = QtWidgets.QLabel(sub)
            self.label3.setGeometry(10, 80, 500, 10)
            self.label3.setText('Default')
            self.label3.show()
        if action.text() == "Change Text":
            for i in self.mdi.subWindowList():
                label1 = QtWidgets.QLabel(i)
                label1.setGeometry(10,50,500,10)
                label1.setText(str(i))
                label1.show()
                self.label3.setText('TRUE')
                print(i)

def main():
    app = QApplication(sys.argv)
    ex = MainWindow()
    ex.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

but it's always the last creating order subwindow that changes https://i.sstatic.net/DjZtf.png

how to change item in every subwindow? how to change text table in subwindow i want with over 10 subwindow?

Right now your label3 is stored in MainWindow, so when you cycle through your subwindows you just change the latest label. You can store it in each subwindow like this:

import sys
from PyQt5.QtWidgets import *
from PyQt5 import QtWidgets


class MainWindow(QtWidgets.QMainWindow):
    count = 0

    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.mdi = QMdiArea()
        self.setCentralWidget(self.mdi)
        bar = self.menuBar()

        file = bar.addMenu("Subwindow")
        file.addAction("New")
        file.addAction("Change Text")
        file.triggered[QAction].connect(self.click)
        self.setWindowTitle("Multiple window using MDI")

    def click(self, action):
        print("New sub window")
        if action.text() == "New":
            MainWindow.count = MainWindow.count + 1
            sub = QMdiSubWindow()
            sub.setWidget(QTextEdit())
            sub.setWindowTitle("subwindow" + str(MainWindow.count))
            self.subwindow = self.mdi.addSubWindow(sub)
            self.subwindow.show()
            # change current subwindow label text
            button = QPushButton("Click to change", sub)
            button.clicked.connect(lambda: sub.label3.setText('TRUE'))

            sub.label3 = QtWidgets.QLabel(sub)
            sub.label3.setGeometry(10, 80, 500, 10)
            sub.label3.setText('Default')

            sub_layout = self.subwindow.layout()
            sub_layout.addWidget(sub.label3)
            sub_layout.addWidget(button)

        if action.text() == "Change Text":
            for i in self.mdi.subWindowList():
                label1 = QtWidgets.QLabel(i)
                label1.setGeometry(10, 50, 500, 10)
                label1.setText(str(i))
                label1.show()
                i.label3.setText('TRUE')
                print(i)


def main():
    app = QApplication(sys.argv)
    ex = MainWindow()
    ex.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()