If a page on your website not anymore exists and you want to redirect it to your new page or website then you need to use the .htaccess file for redirection

Redirect from a page/directory to some other domain or the main domain:

Redirect from a particular page to a domain:
RewriteEngine on
Redirect 301 /mypage.html http://xyz.com

Redirect from a page to another page:
Redirect from a page/directory to another page
Redirect 301 /oldpage.html /newpage.html

Now, when you open the URL xyz.com/oldpage.html, it will subsequently redirect you to xyz.com/newpage.html