According to Algorithm rules,
every page should have a canonical URL. Even if the page doesn't give credit to any other pages.
That's the rule.
If you want a clarification, just refer any of the website (Including yours
). Check the source code and search for "canonical".
Usually we integrate canonical to the header file.
<link rel="canonical" href="http://<?php echo $_SERVER['HTTP_HOST']; ?><?php echo parse_url( $_SERVER['REQUEST_URI'], PHP_URL_PATH ); ?>" />
Thanks and Regards.
Akhil K A