Hello @ZEINEB BEN DHAFER ,
Azure IoT Central is a Software-as-a-Service solution to simplify connecting devices to the cloud, visualizing their telemetry, and sending that telemetry further into Azure.
Azure IoT Central is actually implemented on common Azure IoT Platform-as-a-Service services IoT Hub, Stream Analytics, and TimeSeries Insights.
The Device Provisioning Service also plays a major role regarding simplifying device enrollment:
All you have to care about is connecting your device to IoT Central, ingest the telemetry, and optionally sending those messages to other Azure services like blob storage, event hubs, etc.
Check out this learning path about Azure IoT Central.