Admins or anyone in a role with the correct permissions can manage/moderate content. Content can be automatically flagged to be reviewed via the Review Queue or can be done by simply monitoring the site for individual contribution.
Administrators can set up Automation Rules (Manage > Settings > General > Automation Rules) to establish criteria to have posted content reviewed by Administrators/Moderators prior to being actually published on the community. For example, you can set up an Automation Rule to moderate all content from new members or content that contains certain keywords. You could also set up a rule that only moderates content posted by specific members.
Content that has either been reported by your community members or has been flagged for moderation via an Automation Rule will be listed in the Review Queue (Manage > Review). There, moderators can approve or reject the content. If rejected, the content will be removed from the site.
Administrators and moderators can edit or delete any post that they have access to. For topics, there are additional management tools available -- closing topics, featuring in one or across all forums, creating cross links, and moving a topic to another forum.
Topic comments (or reply) can also be forked into a new topic. Simply go to the topic comment that’s off-topic, and click the “Gear" Icon on the right side. Then click Fork Topic. If there are multiple forums, then choose the correct one from the drop down. It will default to the Forum that the reply is being forked from.