Notices or Comments are used to put up info on an edit page that is only viewable on the edit page. These can be used to inform editors to edit only certain areas of a page, such as under a certain heading.
To create notices, use this code:
<!-- TEXT -->
That gives you:
To use this code, just replace TEXT with the text you want to be only visible on the edit page. You can use either code they both work just the same.