Final answer:
To make a menu item a non-clickable header, select the item in the menu edit area, change its properties to act as a 'Separator' or 'Header', or remove its URL. The exact steps vary with the system being used, with an example being setting the URL to '#' in WordPress.
Step-by-step explanation:
To make a menu item a non-clickable header in a menu edit area, you need to edit the properties of the item. Depending on the content management system or website builder you're using, the process can vary. Typically, you'd select the menu item you want to change and look for an option to either remove the URL or set the item as a 'Header' or 'Separator', which would not be linked to any page. For example, in WordPress, you can use a 'Custom Link' and simply enter a '#' for the URL, which effectively makes the menu item non-clickable. After making this change, make sure to save the menu to apply the changes.