If you’re a team owner, you can automatically favorite up to 10 channels for the whole team, making them show up automatically in everyone’s channels list so people will be aware of important channels.
There are two ways to do this. When creating a new channel, select Automatically favorite this channel for the whole team below the description box.
You can also go to the team name, click More options > Manage team, open the Channels tab, find the channel you want to auto-favorite, and then check the box in the Auto-favorite column.
To see auto-favorited channels on mobile, you might have to sign in to the desktop or web app first.