You need a premium subscription to save songs for offline listening.
With a free account, you can only listen to music when you're connected to the internet. Also, the free account only allows you to listen to albums and playlists on shuffle if you're using a mobile device, like your iPhone 5C.
The premium subscription enables:
- High Quality audio streaming both on desktop and mobile;
- Save songs for offline listening both on desktop and mobile;
- Select individual songs to listen on mobile
i hope this helps 🙂