It is only visible if the particular workbook is active. In the example on this page we add a new menu item, 'FoodMenu', to the right of the standard Help menu. Instead a new menu item is shown, 'AddIns,' and if you click this, you see your own menu. Note: In Excel 2007 and newer you don't replace Excel's built-in menu, and I don't know if it can be done.
They are either added to Excel's standard menu, or you can make your own Excel menu.
In Excel (and other Office programs) it is pretty easy to make menus tailored to your needs. How to make your own menus in Excel with VBA
