Add a Classification Macro on the page to display the Classification Level when exporting the page as PDF or Word.
Simply add the macro in the section of the page where you want the level to be displayed.
The macro can be configured at Settings > Compliance Configuration > Classification > Macro Options
There are three customisable items preface, size and print/export only.
This allows you to add a preface to the text shown in the macro. By default it only displays the name of the Classification Level i.e. "Highly Restricted". Using the field, you can add a text before it. For example, adding "Classification Level:" into the field will display "Classification Level: Highly Restricted" when printed.
This simply changes the size of the macro and text, there are three options: small, medium and large.
When this is enabled, the macro text will only be visible when it is exported - it will be invisible when viewing a page within Confluence.