magento2.2.6 – How to add a canonical tag on mangenot 2.2.6 for a complete website via backend or coding

How to add a canonical tag on mangenot 2.2.6 for the whole website via a backend or via coding when I audit my website with the MOZ Pro software and have its tag display MISSIN Canonical Tag for 864 label pages

Stores> Settings> Configuration.

then expand the Catalog drop-down menu and choose Catalog. Then open the Search Engine Optimization Section:

I choose "Yes" for both

Use the canonical link meta-label for categories – "Yes"
Use the Canonical Link meta-label for products – "Yes"

and save the configuration.
see the picture belowenter the description of the image here

need the right solution and answer for MISSING Canonical Tag for the whole site magento 2.2.6 w