iTunes playlist
I created a playlist and cannot move the songs around in it. It used to be simple to just swipe and place where it needed to be. I have just upgraded to iOS 15.1. Any ideas?
iPhone 11, iOS 15
That option should still be there, see the 'Edit a playlist you created on iPhone' section in:
Create playlists on iPhone - Apple Support
To Change the song order: Drag 
next to a song.