Run Logic app if new virtual machine is created

Try a sample on below:

{
  "definition": {
    "$schema": "https://schema.management.azure.com/providers/Microsoft.Logic/schemas/2016-06-01/workflowdefinition.json#",
    "actions": {
      "If_create": {
        "actions": {
          "YourAction": {
            "inputs": {
              // Your actions here
            },
            "runAfter": {
              "Condition": [
                "succeeded"
              ]
            }
          }
        },
        "else": []
      }
    },
    "triggers": {
      "When_a_resource_is_created": {
        "type": "Microsoft.EventGrid",
        "inputs": {
          "topic": "/subscriptions/YOUR_SUBSCRIPTION_ID/resourceGroups/YOUR_RESOURCE_GROUP/providers/Microsoft.EventGrid/eventSubscriptions/YOUR_EVENT_SUBSCRIPTION",
          "subscriptionId": "YOUR_SUBSCRIPTION_ID",
          "resourceGroupName": "YOUR_RESOURCE_GROUP",
          "eventSubscriptionName": "YOUR_EVENT_SUBSCRIPTION",
          "operationName": "YOUR_OPERATION_NAME"
        }
      }
    },
    "conditions": [
      {
        "name": "Condition",
        "type": "If",
        "inputs": {
          "condition": {
            "equals": [
              "@triggerBody().data.operationName",
              "Microsoft.Compute/virtualMachines/write"
            ]
          }
        }
      }
    ]
  }
}