Often, when creating menu in WordPress that has a drop down menu beneath it, you don’t want the top menu item linked.
To create a menu item that doesn’t link, you want to to add a Link instead of a Page, from the left hand side of the Menus page.
Where it asks you to type in the Link URL, you need to replace the “http://” that has been pre-filled in the form with a “#” (no quotes!).