Channel posting policy
You can restrict who can send messages to a channel. For example, you can set up an announcement channel where only a specific group of users can send messages.
- Click on the gear () icon in the upper right corner of the web or desktop app.
 - Select Channel settings.
 - Click All in the upper left.
 - Select a channel.
 - Select the General tab on the right.
 - Click Advanced configuration to view advanced configuration options.
 - Under Messaging permissions, configure Who can post to this channel.
 - Click Save changes.