Edit podcasts on my iPhone

Delete one episode

1. Open the Podcasts app.
2. On your iPhone, go to the Library tab, then tap Shows. On your iPad, go to Library in the sidebar and tap Shows.
3. Tap the show to see all of its episodes.
4. Find the episode that you want, then touch and hold the episode.
5. Tap Remove Download.

Delete all episodes in one show

1. Open the Podcasts app.
2. On your iPhone, go to the Library tab, then tap Shows. On your iPad, go to Library in the sidebar and tap Shows.
3. Find and tap the show.
4. Tap the More button.
5. Tap Remove Downloads.

Delete all episodes

1. Open the Podcasts app.
2. On your iPhone, go to the Library tab, then tap Downloaded. On your iPad, go to Library in the sidebar and tap Downloaded.
3. Tap the More button.
4. Tap Remove All Downloads.
5. 
   
6. 
7. Confirm that you want to remove all of your downloads.

found this here Download and delete episodes in Apple Podcasts on iPhone and iPad - Apple Support

hope it helps