The Monitor tab is the function's built-in monitoring feature that allows you to explore recent invocation details and logs.
The Monitor tab is very useful during development, but is unlikely to be sufficient for the needs of a production application. In production, especially for functions that scale dynamically and may have thousands of invocations per second, the ability to aggregate data and identify trends is crucial, and thus Application Insights are the recommended monitoring tool.
To see the monitoring of one of your functions, navigate to your Function App -> Function Name -> Monitor.
Here, you will see all the recent invocations of your function along with the success and failure rates. Clicking on a specific invocation will allow you to explore the invocation parameters and logs. You can also see the duration of each function invocation...