How to view and create MS Teams private channels using the Teams Admin center

Step 1: Go to the Teams admin center then Click on “Manage teams”.
  

Step 2: Select a Teams group and then click on the “Channels” tab. You’ll find private channels indicated under the “Type” column.

Step 3: To add a new private channel, click on “Add” in the top-right corner of the tab.

Step 4: Enter a name for the channel and select the type as “Private” then Select the owner(s) from existing members of the Teams group.

 

Credit : https://help.coreview.com/how-to-view-and-create-teams-private-channels