what does it mean that phone must be backed up

[RANDMROOST2]

keep getting message that phone must be backed up what does that mean

[bd94s10 · Accepted solution]

You are more than likely seeing the message that you only have 5GB of iCloud and your device has not been backed up.

Backup means all your contacts, photos, messages, etc. are backed up in the cloud. You can either backup your device via iTunes or via iCloud (plugged into a power outlet and on a Wi-Fi connection).

More info: How to back up your iPhone, iPad, and iPod touch - Apple Support

Hope this helps!