This plugin is used for multilingual websites. By adding an HTML tag to the header of the pages, HrefLang shows the search engines that there are different versions of different languages for the same page of a website. For example, we have a multilingual website with this URL: yourwebsitewebsite.com And hreflang plugin is installed on the website. So, for different languages of the home page, we have different URLs. Now if someone searches the name of your website's name in English in a search engine, the results’ URL will be as : yourwebsite.com/en. and the search is in French, the result will be as : yourwebsite.com/fr This plugin also allows you to specify a url for users whose default browser language is not defined on the website.