Commenting can be enabled on a per-article basis. To enable commenting for articles, navigate to the article’s parent section, hover over the article’s name, then click edit. Navigate to the “Comments” Tab and select the checkbox to enable commenting on that article. Remember to save and publish your changes!
In order to allow anonymous commenting, use the main menu to navigate to Settings > Site Settings. Then scroll down to “Allow Anonymous Comment” and toggle the checkbox to your preference. This setting will apply to all articles which have comments enabled.