how do you create a genius playlist while listening to a song on iphone7

The ability to create Genius playlists from the Music app was removed in iOS 10 (even though for some reason the setting still remains). If you sync your iPhone's music library through iTunes, you can create them in iTunes and then sync them to your phone: iTunes for Mac: Use Genius Shuffle, Genius playlists, or Genius Mixes (this should work for Windows as well). You can also send your feedback to Apple letting them know that you want this feature back: http://www.apple.com/feedback/apple-music.html

The feedback link you provided is to improve Apple Music and has nothing to do with the iOS music app.