In the case of Printable Publications, you have the option to hide pages of your project for certain platforms. Meaning that you can hide pages that will only show in a Print View, or choose to hide pages that will only show in a Desktop/Mobile view.
This feature is developed so that you can create and tailor the right content to your audience when they are viewing your publication from a webpage or in a PDF format. To do this, go to the printable publications' page overview and hover over the desired page and click the Wrench icon for settings. The page settings menu will pop up, go to PDF settings.
When in the PDF Settings tab, this shows the pages different settings for visibility with the desktop (web), PDF and the table of contents. Depending on where you want the page to be visible, you will have to toggle on or off the options to view your publication on the web and/or pdf. Click the Save button in the bottom right of the popup when you are done.
Once you have saved your settings, you will be directed back to your page overview. Depending on your settings, you will notice that the toggled pages now have a grey tag displayed, either saying Web Only or PDF Only. This means that the page is either only viewable on the web with a URL link or is only viewable in a PDF which has been generated and downloaded by the user.