Hi @forouserla,

Forum topics have replies, so I assume you are referring to replies saying comments. Replies cannot be disabled like it is on Blog Posts. This is a forum and all components are controlled by Forum Accesses and Permissions. If you don't want to allow your users to reply in topics you can manage it per forum or per forum access. For example, you can edit the Standard Access in wpForo > Accesses admin page and uncheck the following permissions:

• Can post reply
• Can reply to own topic

More information about forum accesses and usergroup permissions: https://wpforo.com/community/faq/wordpress-user-roles-wpforo-usergroups-and-forum-accesses/#post-39664