To change the values of the WindowState, Width, and Height properties of the Excel application window, you must explicitly reference the Application object

 
Sub changeSize()
    Application.WindowState = xlNormal
    Application.Width = 600
    Application.Height = 450
    End Sub

1.	Transform all windows into icons
2.	Zoom a form
3.	Make sure that the scroll bars and status bar are hidden and that the formula bar is displayed:
4.	Zooming a Window and Setting Display Options
5.	Set the window position and size
6.	Center application

To change the values of the WindowState, Width, and Height properties of the Excel application window, you must explicitly reference the Application object : Application Windows « Application « VBA / Excel / Access / Word