How to Remove "Leave a Reply" in WordPress Site?

1, If you want to disable comments for your all future posts or pages, go to Settings > Discussion, then uncheck the box “Allow people to post comments on new articles” in Default article settings section. 
2, In case you only want the comment section won’t be displayed on certain pages, you can do that by following these steps: 
 Step 1: Go to your wp-admin area. Then scroll down to the Pages section, click All Pages.
 Step 2: Choose the page that you want to remove “Leave a reply” box, then click Edit. 
 Step 3: Click the Screen Options tab on the upper right of the dashboard. Make sure the box “Discussion”is checked in this tab.
 Step 4: Next, move to the bottom of the page to find the Discussion section. 
 Step 5: Uncheck the option “Allow comments” in the Discussion section and save the changes to the page by press “Update”