Are you using a theme from our theme store? If so, you do not need to worry about adding canonical tags!
We've built-in Google-friendly canonical URLs, so your SEO is not impacted by "duplicated" content.
On the internal, it's common for the same content to be accessed through multiple URLs. For example, there are two ways to access the mug in this storefront:
Canonical URLs are the authoritative or primary URL that's served to Google. Usually, they're the shortest URL. In the above example, the second URL is the one that would be picked up by Google.
We have a canonical URL for all URLs at Shopify (products, collections, pages, and blogs), so there is no risk of duplicate content.
I hope this helps!
This is an accepted solution.
You do not need to worry about this as the way our themes are built ensure that duplicate content will not be indexed by Google.