Thats where private channels come into play.
Theres nothing complicated about making your public channel in Slack private.
For this, you gotta go to its configs and click Change to a private channel.
Valeriy Odintsov
You should also know that files shared before you made the channel private will still be available.
Okay, lets see how it works in more detail.
Only invited users have access to the conversations and files in them.
For some reason, this option is not available on mobile.
But you could turn your existingconversation into a private channel.