Provided you have the necessary rights, you can see in the portal who has commented which message and, of course, make comments.
Please click on "Memos" in the main menu on the left
Now please select the desired message on the right side of the main menu for which you want to make comments and then click on the item "Comments".
Here you will find the input field "Comment". "where you please click once...
If you have written your comment, please click on the symbol with the paper aeroplane
and your comment will be displayed here in the portal as well as to the employees in the app (optical and acoustic)
In this article you can read how to make comments in the app