If I run Icloud backup, will the backed up files be erased from my phone?
If I run Icloud backup, are the stored files from my phone removed, transferred to the backup storage, or are they retained in both locations?
iPhone 5s, iOS 8.2
They are kept in both locations. The copy in iCloud would only be used in the event of a problem that caused you to need to restore to your phone or if transferring to a new phone. More info: About backups in iCloud and iTunes - Apple Support