Configure who can subscribe to a channel
You can give users permission to subscribe to a channel. Everyone other than guests can subscribe to any public or web-public channel, so this feature is intended for use with private channels. Guests can never subscribe themselves to a channel.
This permission grants access to channel content: users who are allowed to subscribe to a channel will also be able to read messages in it without subscribing.
If you have permission to administer a public channel, you can configure who can subscribe to it. For private channels, you additionally need to have content access in order to change this configuration.
- 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 Subscription permissions, configure Who can subscribe to this channel.
 - Click Save changes.