What Is The Difference Between iCloud Sync and Structured Cloud Sync?
iCloud sync and Structured Cloud sync are two different options to sync your data across devices.
However, the iCloud sync is only available for Apple devices, whereas Structured Cloud sync can be used to sync data across Apple and Android devices as well as the Structured Web version.
You can learn more about how to sync Structured across your devices and how to switch between the different sync solutions here.
Which Sync is Enabled on my Apple Device?
You can check which sync solution is enabled on your device by opening your ⚙️ Structured Settings and checking the very first entry in the General section, whether it says iCloud Sync or Structured Cloud Sync.
Please note, that it is not possible to use both sync solutions at the same time. Meaning, you cannot enable iCloud sync on one device and Structured Cloud on another device.