With cloud services, you have the ability to buy resources and/or services directly from your management portal.
That said, it has been always complicated to then match up ordered resources with your internal purchase orders (POs).
Well, now you can reconciliate these when using Amazon Web Services by accessing your AWS Billing and Cost Management portal (https://console.aws.amazon.com/billing/) and then access the new Purchase orders blade available under the Billing section
Then you can match up your PO with the billed resources by clicking on the Add purchase order button available at the top right
Then you define your PO details (PO number, billing…) and finally your item(s)