Explanation
Azure Functions is the simplest option if you are just getting started using the change feed. Due to its simplicity, it is also the recommended option for most change feed use cases. When you create an Azure Functions trigger for Azure Cosmos DB, you select the container to connect, and the Azure Function gets triggered whenever there is a change in the container. Because Azure Functions uses the change feed processor behind the scenes, it automatically parallelizes change processing across your container's partitions.
Note: You can work with change feed using the following options:
* Using change feed with Azure Functions
* Using change feed with change feed processor
Reference:
https://docs.microsoft.com/en-us/azure/cosmos-db/read-change-feed
https://docs.microsoft.com/en-us/azure/cosmos-db/change-feed-pull-model
https://docs.microsoft.com/en-us/azure/cosmos-db/read-change-feed#azure-functions
https://docs.microsoft.com/en-us/azure/cosmos-db/change-feed-pull-model#using-feedrange-for-parallelization