Both the Organizer and all Participants are able to send and receive messages during a conference.
From an active conference, select Chat and enter a message.
If the slide-out menu appears, you'll receive messages there as well. Without the slide-out menu open, new messages are displayed in the top-right corner of Dialpad Meetings.
Keep in mind that Admins are able to enable or disable chat for team members.
Looking for a log of messages from a conference? First, ensure that you've enabled this in your conference settings. Once you've done that, future logs of messages will appear in call summaries.