Take note that Should your shop has presently been indexed by Google or every other search engine, it'd just take some time for your improvements to appear in the search results... You may have to Wait and see! The title of the store by itself is set in the installation https://www.presta-addons-modules.com/en/seo/prestashop-seo-automatic-hreflang-tags-canonical-tags-on-all-pages.html