Search engine optimization suggests "Search engine optimisation". It signifies a list of tactics and best methods aimed at increasing the visibility of an internet site on serps.   You specify the first URL as the search engine might have issues pinpointing which one ought to be the principal URL.  The https://www.presta-addons-modules.com/en/seo/prestashop-seo-automatic-hreflang-tags-canonical-tags-on-all-pages.html