Qt Widgets includes a robust layout system to control the presentation of widgets on the display. In Qt Creator Designer, you can pick from the following layouts:

Using one of these layouts is easy: simply choose the appropriate layout in Qt Creator Designer and drag it to the widget or window you're building. If you're constructing a hierarchy of widgets in the code, you add the widgets to the layout and set the parent widget's layout, like this:

QWidget *window = new QWidget();
QPushButton *button1 = new QPushButton...