While the event is going on, each attendee is free to ask questions to the presenter through a form in the web browser. The questions can be filtered by a moderator before being displayed to the presenter, who can then answer them on camera.
However, there is a way to make the approved questions visible to all attendees, reducing the occurrence of duplicate questions and making the moderator's job easier.
Activate it in the "Basics" setting page:
Now, when you start the event, your attendees will be able to ask questions. For example:
One attendee, on Chrome, asked a question, and another, on Firefox, asked another one.
Both questions have been approved, and each attendee can see not only their question, but also the other one's.