To delete an iteration in Azure DevOps, follow the below steps

Step 1: Go to Project Settings

Step 2: Click on Project Configuration

Step 3: Click on the “3” dots next to the Sprint or Iteration you want to delete

You will see something like this

Step 4: Click on “Delete” and then you will get a confirmation popup, where click on “Delete Path”

Step 5: Once you have clicked on “Delete” path, Iteration will be deleted.