Create a function, with the help of a blob trigger template, which is triggered when files are uploaded to or updated in Azure Blob storage.
You use a consumption plan, which is a hosting plan that defines how resources are allocated to your function app. In the default Consumption Plan, resources are added dynamically as required by your functions. In this serverless hosting, you only pay for the time your functions run. When you run in an App Service plan, you must manage the scaling of your function app.
References:
https://docs.microsoft.com/en-us/azure/azure-functions/functions-create-storage-blob-triggered-function