For some WordPress sites you may not want to allow commenting on any of your posts, pages, products etc…
If it’s a new site then turning them off at the beginning is simple to do with the following steps.
Page & Post Level Comment Controls
Open up your page/post editor and select “Screen Options” from the drop down and check “Discussion” to ensure you have the discussion options viewable on your screen.
Scroll all the way down and uncheck “Allow comments”
This page/post will no longer show or allow comments.
Disable all future comments on posts
Navigate to Settings -> Discussion within your WordPress admin area and uncheck “Allow people to post comments on new articles”
The above works if your site is new without any new content.
If you have an existing site and posts already created and comments are allowed, but you don’t want to click through each post to disable comments manually, there’s an easy fix.
Navigate to Settings -> Discussion in your WordPress admin area and check “Automatically close comments on articles older than 0 days”
Disable All Comments Globally
Lastly and probably the easiest solution, install Disable Comments plugin. Installing this plugin will disable comments on all or any you configure within the plugin right after install. I like this option as all the permissions are all in one place and very easy to configure.
You can pick up this plugin for free here: https://wordpress.org/plugins/disable-comments/