There may be not any totally free addon for putting in Google Tag Manager in PrestaShop besides buying a compensated addon. Prestashop also doesn’t give use of Web site code so we are able to increase Tag Manager code but there's still an alternate way by immediately modifying the website https://www.presta-addons-modules.com/en/seo/prestashop-seo-automatic-hreflang-tags-canonical-tags-on-all-pages.html