The nature of Search Engine is to Crawl websites that are available on the search engine. Once a website gets live and cache on search engine, Google has a right to visit the website and start indexing the online content and images of the website. It is definitely a good procedure if search engine frequently visits the website. But, if the owner of the site doesn’t want some of the pages to be crawled and cached on the site, then Robots.txt is used on the site. It is a text or file that professionals use on their sites which tell search robots to not visit some of the specific pages, but it is a myth that it stops the search engine to do not visit the page. It is just like putting a note i.e., “Please do not enter”. As search engine obeys the message of site so it doesn’t visit those pages where this kind of note or Robots.txt is placed.
It is one of the most popular ways from which professionals can prevent from the risk of being imposed a duplicate content penalty. On the other hand, it is necessary to place it appropriately at the right place otherwise if the search engine doesn’t find it then it will Crawl the entire site or leaves the entire site without crawling. Thus, it is necessary for professional to go for a deep analysis or study before imposing this Robots.txt on the site. Robots.txt is not mandatory for professionals so, it is professional’s choice whether to use this txt file or not.