Switch off/on visibility of pages
In "Page Settings", you will find an option for "Page Visibility"
For any page, if you would like to disable the page so it's no longer visible to guests, then uncheck the toggle switch so the page can no longer be accessed.
At any time, you can always come back to a page to enable or disable it again. This gives you a simple way to quickly toggle a page in case you want to make any edits or bring down a page.