About this app
There are no ways to edit canonical tags or urls in Shopify and that's where this app comes into play.
Canonical Tag/URL Manager makes it possible to edit canonical tags for any of your products, pages, articles and collections.
This is beneficial to your store if you want to point search engines to a different version of a page for example, if you have multiple versions of the same product but you want one to get all the juice then modify its canonical url to let search engines know.