To disable comments on a page just edit the page and click the “Screen Options” tab at the top right of the screen. A little slidedown will appear with various checkbox options on it. Check the “Discussion” option.
Once you’ve done that you will see a checkbox at the bottom of the page labelled “Allow comments”. Uncheck this and save the page. Your page will no longer display the feedback form and users will no longer be able to leave comments on it.
When you edit or add any future pages you will now see the “Allow comments” checkbox at the bottom of the page and can just deselect it for any pages that you don’t want to display the form.