var ATargetWindow := FindWindow(nil, 'Untitled - Notepad');
if ATargetWindow = 0 then
    Exit();

var ANewRect : TRect;  // Or := Rect(..,..,..,..)
ANewRect.Left   := 10;
ANewRect.Top    := 10;
ANewRect.Width  := 400;
ANewRect.Height := 200;

// Just Move Window
SetWindowPos(ATargetWindow, 0, ANewRect.Left, ANewRect.Top, 0, 0, SWP_NOZORDER or SWP_NOSIZE);

// Just Resize Window
SetWindowPos(ATargetWindow, 0, 0, 0, ANewRect.Width, ANewRect.Height, SWP_NOZORDER or SWP_NOMOVE);

// Both
SetWindowPos(ATargetWindow, 0, ANewRect.Left, ANewRect.Top, ANewRect.Width, ANewRect.Height, SWP_NOZORDER);