Hello Yusuf,
When you share your screen with people in a Topic, your chat window is active and everyone can collaborate and comment on what they are seeing, in real time. The comments will not be on the document you show them, but in your Topic discussion. You can also send the file to the audience and they will be able to work on it in their terms; once they are finished commenting, they can upload the modified file on the thread.
Hope this helps!
