So you want to hide a page in your website from the Search Engines. This can be easily done by just adding a Meta tag in the head section of the page which you don’t want to be indexed by the Search Engines. In this way you will be telling the robots (Search Enignes) not to crawl that page and not to store it in their search database. For this that page in your site will not show up in any search results and users will not be able to find that page through searching in Search Engines.
This is the Meta tag that you will need to add in the head section of that page.
<meta name="robots" content="noindex, nofollow" />
This will prevents robots to crawl that page and will not be indexed.
So from now prevent user authenticated pages and duplicate content pages in your website to appear in Search Engine Results Pages (SERPs) and thus prevent unauthorized access to those pages.