How to customize existing PO Print Out (Proforma Purchase Order )

Dear Member,

Please how can I customize an existing PO report ( Print Out (Proforma Purchase Order ) in AX 2012.

Kindly assist me on steps to follow or manuals to read.

Best Regards

Look at Technet: Reporting in Microsoft Dynamics AX.

And here you can find details about the particular report, such as which class is responsible for preparing the data: Purchase order report (PurchPurchaseOrder).