Once you have installed and enabled the Custom Canonical plugin you can change its configuration settings.
Settings
There are six settings you can change in the plugin. They primarily change where canonical tags are allowed to be set.
Root URL: Enter the base URL for your Joomla installation e.g. https://www.danielmorell.com. This is used for setting the domain for relative URLs.
Remove Default Canonical Tags (Recommended): Set to Yes to remove the default canonical tags that Joomla places on articles. The core canonical tags are often wrong. This is recommended.
Article: Set to Yes to include canonical URL field in articles.
Category: Set to Yes to include canonical URL field in content categories.
Tag: Set to Yes to include canonical URL field in tags.
Menu Items: Set to Yes to include canonical URL field in menu items.
Note: If you set any of the canonical URL fields to No it will remove all canonical fields from that view/item type on the front end.