Types of conversations
When you create a conversation, you choose between a direct message and a named conversation. Both organize a conversation around a group of people, but each works differently.
Direct messages
Use a direct message to reach a defined set of people that will not change over time. Direct messages are always private.

Named conversations
Use a named conversation to organize around a topic, where the members may change over time. A named conversation can be made public or findable within a workspace, so new people can find it and join.

Turning a direct message into a named conversation
If a direct message outgrows itself, convert it rather than starting again:
- In the DM, tap ⋯ in the top right for Conversation Settings.
- Tap Members.
- Tap Convert DM into Named Conversation.
- Name it and tap Convert.
The history comes with it, so people who join later can see what was already said, and you get the access controls a named conversation has.