Participants are able to message one other participant at a time, using the Participants page or Moodle messaging.

Trainers can send more pressing or urgent messages to a group of participants, or all participants in a learning event, as follows:

Go to the Participants page.
Select participants from the list or use the 'Select all' button at the bottom of the list.
From the 'With selected users...' drop-down menu, choose 'Add/send message.'
Type the message, then click the 'Preview' button.
Assuming you are satisfied with the message, click the 'Send' button.