If You would like canonical url in the html header you'll have to put in writing or obtain a module for that as It isn't included in Prestashop. In PrestaShop, Hreflang tags and canonical tags are utilized to assistance engines like google fully grasp the relationship in between different variations https://fatallisto.com/story7413578/was-ist-ein-canonical-tag-things-to-know-before-you-buy