There are several reasons you may want to disable commenting in WordPress. The most common reason is that you are using WordPress for some type of site other than a blog.
There are a variety of workarounds to disable comments. The simplest is to go to “Settings ==> Discussion” and un-check the box that says “Allow people to post comments on new articles”.
Unfortunately, this can be a hit-or-miss because, as the warning on that page says, “These settings may be overridden for individual articles.”
Because of this, many find it easier to install a simple plugin that makes disabling comments easier to control. Here’s how to do it:
From your WordPress dashboard navigate to “Plugins ==> Add New”.
In the search box type “Disable Comments” and click “Search”
The “Disable Comments” plugin should be the first result. Click “Install Now” and then click “Activate Plugin” on the next page.
Navigate to “Settings ==> Disable Comments”. Select the options you want and click “Save Changes”