Home Sharing is a setting in iTunes that lets other iTunes (Mac or PC) or iDevice users see the iTunes library on your Mac or PC (including when the library is hosted on the DiskStation). Your iTunes is linked to the iTunes Store with an Apple account. Others can log access your Mac or PC library using that account name and password, including being able to drag from your library and drop into theirs.
Synology's so-called iTunes Server (firefly) doesn't support Home Sharing, but only the old network sharing originally in iTunes. IMO, it's worthless, so we use Synology's Audio Station and DS Audio app.
The reason I asked was because you can drag and drop from your iTunes library into hers.
My wife and I each have our own iCloud accounts for email, etc. but in iTunes, she uses my iTunes Store account. That way, we can both use purchases from the iTunes Store (mainly iOS apps).
DS 1512+ w/3GB, 5 x 3TB Seagate ST3000DM001 8.2TB RAID 6, half files/half Time Machine.
Icy Dock MB559U3S-1SB enclosure w/4TB Hitachi UltraStar via USB 3 for files backup
UVERSE to AirPort Extreme + 2 AirPort Express w/speakers. TRENDnet TV-IP312WN camera
CyberPower CP1500PFCLCD Sine Wave UPS
DSM 4.1-2661 w/SSH + SFTP, VPN Server, Syslog Server, Media Server, Mail Server, Mail Station,
Audio Station, Surveillance Station, Photo Station, Web Station - DS Apps on iPad & iPod Touch.