There are three kinds of backup available:
-Manual Backup: You can do a full backup just by tapping on the (+) button. You can share your restore point by email for later restore. Erasing this backup does not erase the backup made to iCloud.
-Auto Backup: If you enable this feature, your data will backup automatically once a week. The last two restore points are stored in the device. Erasing this backup does not erase the backup made to iCloud.
-iCLoud Backup: You can back up all your data to iCloud and share it among all your apple devices. This backup is independent from the backups in your device. Erasing this backup does not erase the backup stored in your device. This feature needs the iCloud service to be enabled on your device.