There are three different types of chat options available in the MeritHub virtual classroom. Click on the chat option present on the left side of the window.
The first one is a public group chat feature in which your message will reach every participant in the session.
The second one is a private chat feature in which you can message someone privately and other participants will not be able to see your message. By default student-to-student private chat is enabled but MeritHub support team can disable it on your account.
The third one is for students i.e; if they want to ask the host/teacher any question and only the host will be notified about your message, not other students. Refer to the below images for more info.