If you have non-HTML pages on your internet site, for instance PDFs or spreadsheets, you won’t be capable to apply hreflang while in the of the HTML because it doesn’t exist.  Evaluate the groups of duplicates. Decide a person canonical version that should be indexed while in the search results. https://addons.prestashop.com/en/seo-natural-search-engine-optimization/31857-automatic-google-rich-snippets-json-ld-open-graph-seo.html