There's a few chat applications which can be used to communicate:


===== Secure =====
  * SimpleX - Bit more secure then Signal, as it has built in privacy features at the protocol level (such as message padding). By default users /chats don't have constant identifiers either. Allows for anonymous profiles and supports multiple profiles.
  * Signal - Good replacement for normal "text messaging". Share your username instead of phone number.
  * Delta Chat - Supports multiple profiles.


===== Less Secure =====

  * Keybase - Supports multiple profiles, allows managing teams. Roughly an alternative to discord/slack. Currently owned by Zoom. Keybase has access to metadata to understand who is talking to who. https://book.keybase.io/docs/chat/crypto#metadata

===== Treat As Public Chats  =====
  * Matrix - Fluffychat client is recommended, as it supports multiple profiles. Setup a home server and disable federation to prevent metadata being copied around. Note Homeserver owners can join encrypted chats and impersonate users.