See history of a supplier accepting a PO or submitting an invoice?

How do I see the history of a supplier accepting a purchase order or submitting an invoice?

• Firstly, click onto the job you want, go to the costs tab and then click on the relevant cost. 
• You should then see the 'Action History' button. 
• Click this and it will reveal information such as when purchase order was sent, if the purchase order has been accepted/cancelled, if an invoice has been submitted or resubmitted.

If you wish to see when an order has been marked as delivered / goods receipted you can see this further down in the cost history.