How to add my Ontario licence in my Apple Wallet

Refer to this support article. I provided a link to the Canadian version

Add your driver's license or state ID to Apple Wallet - Apple Support (CA)

The link you provide is ok and is in fact a canadian page. The text is a copy/paste from the US site and the included links refer to US stuff. You are probably right, Wallet is not fully fonctionnal in Canada.

You can contact Apple Canada and see if they know differently. Although Apple has regional versions of its pages, many are essentially identical since most things don't vary country to country. I usually don't bother forcing my links to specific countries because then somebody clicking on a link will have it render in the language to which their account is set.

This page has telephone numbers for contacting Apple for support and service ➞ Contact Apple for support and service - Apple Support

Quite the contrary. The URL I provided (have a look at it and you will see I forced it to the Canada, English version) specifically forced it to the Canadian version of that page. If you are not seeing a way to do it for Canada then it is likely no such method exists.

This article relates to USA, not Canada.