Magento 2 Canonical Meta Tags are tags used in the HTML code of the page in order to define the original content URL to avoid duplication issues.

That is why it is important to set canonical tags for your Magento Blog pages to improve your blog SEO.

In order to use canonical meta tags for your blog pages navigate to Stores > Configuration > Magefan Extensions > Blog and find the Search Engine Optimization section. There choose pages you want to Use Canonical Link Meta Tag For.

Magento 2 Blog SEO Configuration

Once you finish don't forget to Save Config. As an alternative, you can enable canonical tags for blog and other website pages as part of the Magento 2 SEO Extension.