You can prevent Google (and other search engines) from indexing a page on your site by setting a password or adding a "noindex" tag.
Note: The page may still appear in search results, even after following these steps to hide it. In this case, request a reindex by verifying your site with Google Search Console.
Use a password for private pages
Setting a site-wide password prevents your entire site from being indexed. This is a great option if your site is for internal use or still under construction.
You can also block individual pages using a page password. Placing pages behind a password is useful for pages only clients or internal contributors should access.
If search engines indexed your site before you added a password, your site will appear in search results until it's indexed again.
Use "noindex" tags for public pages you want to hide from search engines
To hide your entire site or specific pages from search engines without hiding them behind passwords, add a “noindex” tag.
To add the tag, you can check Hide this page from search results in the SEO tab of Page Settings, or add it via Code Injection. To learn more, visit Adding noindex tags.
Disable a page
Disabling a page hides it from both visitors and search engines. When logged into your site, you'll see disabled pages in the Pages panel, but they won't appear in navigation or be accessible to visitors.
Use Google's Remove URLs Tool
Not Linked pages still appear in search results
The Not Linked section is for pages that don't need to be featured in your navigation menus, but it doesn’t hide them from search engines. To keep pages in your Not Linked section out of search results, use one of the above methods.
Pages within Index Pages
To completely hide the content of an Index Page from search engines, password-protect the Index Page itself and all the sub-pages within the Index separately.
Note: Stacked Index Pages don't support individual page passwords. Setting a password for the Index Page protects all its sub-pages.