Resizing and repositioning windows on the PC desktop is such a fundamental task that you’ll almost do it without thinking. Move the mouse to the title bar/ border, click, drag, release. Very basic, very simple – but there might still be room for improvement.
KDE Mover-Sizer is an open source, portable tool which brings a common Linux desktop trick to Windows. Instead of having to move your mouse cursor to the title bar or border, you just hold down the Alt key, then left-click anywhere inside a window and drag to move it, right-click and drag to resize it.