If you need to have focused, private conversations with people on your team, create a private channel.
Most channels are standard ones — everyone on the team can see them as well as view and participate in conversations, share files, and more.
With a private channel, members of a team must be specifically added to it to participate, see content, and to see the channel appear in their list of channels.
Note: Team owners can create private channels, and allow members to create them. Whoever creates a private channel can add people to it.
Create a private channel
Go to a team you want to create a channel for, select More options > Add channel.
Type a name and description.
Under Privacy, select the down arrow and choose Private - Specific teammates have access.
Type in the names of who you'd like to invite including guests.
Note: People must already be members or guests of a team to be added to a private channel.
Select Add, change anyone's role if needed, and select Done.
People you've added will see it appear in their channel list with a lock next to the name. To add people, see current members, and view private channel updates, select the Open people pane.
Meet Now and share a file
To meet with just the people in a private channel, select Meet now.
When you share a file in a private channel, it's viewable and accessible only to people with access to the channel. These shared files live in a separate SharePoint site away from the standard channels. This ensure access only to members of the private channel.