Not sure which theme you are using. But if you go into the editor, the templates are listed on the right hand side. Look for page template. Find this string of code: and remove it. Update file, refresh your live site and it will be removed. Repeat the same for post template, the code string is the same. Worked great for me.
If you would like to stop people from commenting, go to the Page or Post you want to remove the comments area from and click “Quick Edit”. From there, uncheck the “Allow Comments” button and wallah, no one can leave a reply because the entire section disappears from the page or post.