The robots.txt tells engine crawlers if they are allowed or disallowed to request specific pages and files from your website. We use a robots.txt mainly

The Robots meta tag provides directions to crawlers on how to present your websites to engines. Those directions are in the form of an HTML

The canonical tag informs search engines, which, between several pages, is the master one. Using a canonical tag can help avoid duplicate content errors.  The

The meta description tag is an HTML element used to describe a web page. Meta descriptions appear after the Title and URL within the Search

The title tag is an HTML element that defines a document’s title. You can see the contents of the title tag in your browser’s page