The new update is available on iPhone 6S and newer (including iPhone SE), iPod Touch 7th gen and iPad Air 2 and newer, iPad Mini 4 and newer, iPad 5 and 6 and the iPad Pro models.
The 5 new iOS 13 features are:
1. You can select to have all unknown callers go to voicemail. Anyone not in your contacts or mail or message history will not get through.
2. Quicker and easier selections from the Control Center for wi-fi and Bluetooth.
3. Swipey keyboard with auto correct
4. Dark mode across Apple apps, can be programmed to begin and end at sundown and sunrise.
5. Video editing capabilities within the Photos app.