Google Shop

Hi,

You can find more information on that error here:
support.google.com/webmasters/thread/225...-canonical-url?hl=en
Basically, it means that you have several URLs leading to the same page.
I checked your website but I didn't see several ways to access the same page, so I'm not sure what's going on. I would need a concrete example with the URLs involved to be able to say more on the reason.
Supposing that the issue is with product pages or listings, in each product and category in the HikaShop backend, you have a "canonical URL" setting, where you can provide the main URL you want to be used.
For example, for the product on the page artisan-pens.com/index.php/pencils/product/40-makore you can provide the canonical URL index.php/pencils/product/40-makore
Also, I can see that you apparently have the joomla system SEF plugin which generate false canonical URLs on your pages. I would recommend disabling it as it's creating more problems than it is solving ( github.com/joomla/joomla-cms/issues/25448 ).
Once you have canonical URLs in your products (and categories ?) and you turn off that SEF plugin, these errors from Google Merchant should hopefully disappear.

Hi,

So, based on what you said now, just providing the main URL of the products in their "canonical URL" and having the SEF plugin turned off will fix these Duplicate issues.

For the contact us page, the thing is that there is only one URL to access it. All the links to it on the different pages are the same, so it's not a problem.

Yes