The officially launched with Android 6.0 Marshmallow and while there were some beta releases for Android 7.0 Nougat, there is no official Android 8.0 Oreo update for this device.
Since this requires wiping your data, use the Oppo Clone Phone or a PC backup tool first. Where to Find Downloads oppo f3 android 8 update download
The device will automatically check the Oppo Update Servers for any available OTA (Over-The-Air) packages. If an update is found, tap . Running Android 8.0 via Custom ROMs The officially launched with Android 6
The latest stable official firmware remains based on Android 6.0 (ColorOS 3.0). oppo f3 android 8 update download