If you'd like to set a custom made canonical URL for a selected merchandise, classification, CMS, producer or provider webpage, then go to the configuration of the webpage, opt for the option "Tailor made URL" and publish the customized canonical url of your respective option. Canonical URLs are applied to https://addons.prestashop.com/en/seo-natural-search-engine-optimization/31857-automatic-google-rich-snippets-json-ld-open-graph-seo.html