Only owners of a channel will have the ability to make edits to the channel's information. Customize your channel and set the tone with an announcement banner and descriptive channel topic.
Go the channel you'd like to edit.
Click on the "i" icon at the top right of the channel.
A screen will pop up on the right side, showing the channel's information.
Click on "edit" button to make edits.
Here you can change the channel's name, description, announcement banner, topic, privacy setting, and more.
Be sure to click "save" to save any changes!