While the comment system in WordPress works really well and can be a great way to get feedback, there are many instances when comments from site visitors are not necessary or appropriate. By default, the option for a site visitor to leave a comment is on. This guide will outline the various ways you can disable past and future comments for any Page or Post and hide comments from any past Page or Post.
Disable all future comments
Disable old comments
To turn off comments on previously published content you will need to click on Posts > All Posts in your dashboard (or Pages > All Pages). From there you can either select all the content by checking the box at the top of the column beside the word 'Title' then selecting Edit and then hit Apply from the Bulk Action menu. What happens next is the Bulk Edit section expands and on the right hand side you will see a dropdown box labeled 'Comments'. From there all you will need to select 'Do Not Allow' and click update, and you have disabled comments on your previously published material.