Playlists added to a user's My Music account can be edited using the green "Edit" button.
Click "Edit" to reveal edit and delete playlist modes.
In Edit-mode, users can rename playlist, artist, add notes as well as re-order track order of playlist. After necessary edits, Save Changes.
In Delete-mode, selected playlist will be removed from a user's My Music account.
See next article "How to cache music for offline playback?".