Podcast show notes capture an Episode’s key points and highlights in a visual, written form. They should NOT be a transcription or an exhaustive recap of what was discussed.  Instead, your show notes should provide a summary touching on the major topics covered, highlight background information about guests, and point the listener to additional resources to advance their knowledge of the covered topics.  These resources could include links to related articles,  publications, or products/service;   or actual clips from the Episode itself.
Show notes enable text-based algorithms to identify and make your podcast visible on major search engines, and can be a valuable resource in improving search ranking. They also provide visual information to your listeners to reinforce what they have heard, while making outreach, action, and information sharing much easier. Finally, show notes make it easier for new listeners to jump aboard your Podcast Series and assist returning listeners in keeping track of previous Episodes.