Navigate to your BuddyBoss - Settings - Activity. Under Activity Settings, you will get the Edit Comment. By checking the box you will allow members to edit their comment for a particular duration or Forever. Don’t forget to hit the Save Settings button. 

Move to your Activity Feed and write a comment in any post. Now hit on the ellipsis (3 dots), a drop down menu will appear with Edit, and Delete. Hit on Edit option. 

You can now make changes in your comment like changing texts, adding images, videos, emojis, documents, or GIFs. Let’s add a photo in your comment. If you exceed the maximum size then you will see a warning message like the image below. 

After resizing the image we upload the image again and don’t get any warning message then. 

Here is the edited version of your comment with an image. 

This is how you can allow your members to edit comments.