@MMchen: So, this means that you want to disable the comment function of WordPress. Since you are using Catch Box Free theme where we have use default comment system and there in no option to do that easy from “Theme Options” panel but if you have pro then it’s really easy just from “Theme Options” panel. See more details about Catch Box Pro at http://catchthemes.com/theme-instructions/catch-box-pro/.
There is default option to remove comment box from all free themes. First, you need to go to “Settings => Discussion”. Then in “Default article settings”, just uncheck “Allow link notifications from other blogs (pingbacks and trackbacks)” and “Allow people to post comments on new articles” and Save Changes. This will remove comment system from all new posts and pages. But this will not remove it for your existing posts and pages.
To remove the comment system from your existing post and page. You need to edit that particular post or page. Then in you will see “Discussion” box under your post/page editor. If that is not showing then you need to enable the “Discussion” box from your “Screen Options” at top of post editor. Then from the “Discussion” box you need to uncheck “Allow comments” and “Allow trackbacks and pingbacks on this page” and update page/post.