In case you need to change something in posted topic or reply you can use Edit button. This button is available for all posts and replies.
Regular forum users are not allowed to edit own topics and posts whenever they want. There are time-frames for this purpose. And this time-frames can be set using according options in Dashboard > Forums > Settings > Topic & Posts admin page:
Edit topic and post buttons are only available for Usergroups who have following permissions in granted forum access (by default all except guests):
- Can edit own topic
- Can edit own replay