from PySide6.QtWidgets import QApplication, QWidget, QMainWindow, QPushButton, QLabel, QLineEdit, QHBoxLayout, \
    QVBoxLayout
import sys

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        self.setWindowTitle('my App')
        self.setMinimumSize(400,300)

        self.label=QLabel()

        self.input=QLineEdit()
        self.input.textChanged.connect(self.label.setText)

        layout=QVBoxLayout()
        layout.addWidget(self.input)
        layout.addWidget(self.label)

        container=QWidget()
        container.setLayout(layout)

        self.setCentralWidget(container)

app = QApplication(sys.argv)

window = MainWindow()
window.show()

app.exec()