All Rafts have a Chat tab by default. This is where everyone in the Raft can send messages back and forth to each other to get valuable two-way information. Channels also have a Chat section (messages are the primary content type for Channels). Each Chat page on a Raft or Channel has a message composer bar into which you can directly type your message, which can include images, files, GIFs, and videos.
If you ever want to mute Chat on a specific Raft or Channel directly, select the "Info" ( i ) icon at the top of the Raft or Channels page, or go to the Messages or Rafts section of the notifications settings.
To notify everyone in a messaging group, include @everyone in your message.
To learn more about other types of messaging on Raftr, check out the following articles: