How to change channel posting permission levels and discovery options
Channels have two main permission settings: discovery and posting & commenting permissions. Channel editors and owners can change the permissions from the channel settings.

Discovery:
Set the discovery option for this channel. By default the discovery is restricted.
- Restricted (default) - Not visible in discovery, joining by sharing.
- Ask to join - Visible in discovery, anyone can ask to join from the discovery view.
- Anyone can join - Visible in discovery, anyone can join automatically.
Posting & Commenting permissions:
Set who can create posts and comments in the channel discussion.
- Anyone can post and comment (default).
- Anyone can comment, but posting is restricted to channel owner and editors.
- Only the channel owner and editors can comment and post.
