MS Flow - How To Trigger When Item Is Updated

Introduction 

 
How can I trigger flow only when an item is updated, and not if an item is created?
 
MS Flow provides automated flow for:
  1. When an item is created – it will trigger when any new item is created in the list
  2. When an item is created or modified – it will trigger when a new item is created or any existing item is updated
But MS Flow did not provide an automated flow that only triggers when an item is updated. So when you have a requirement to trigger a flow only when an item is updated that should not trigger when an item is created, you need to use it when an item is created or modified through the automated flow template.
 
Later in this template, we can compare the created DateTime and modified DateTime. 
 
For this, you can add the condition control for if the item’s created DateTime is not equal to the modified DateTime. In the true section, you can add the action which you want to perform when an item is updated, as shown in the below screenshot.
 
 
 
I hope this blog will help you with your common use case of MS Flow.