import QtQuick 2.12

Item {
    id: root
    width: 600
    height: 300

    TextInput {
        id: qwe
        width: 500
        height: 100
        font.pixelSize: 50
        text: "123456"
        focus: true
    }

    Timer {
        running: true
        interval: 500
        onTriggered: {
            qwe.insert(0, "***")
            qwe.remove(0, 3)
        }
    }
}