Lanai,
When you say PO you mean Purchase Order correct? If yes,
1. Search for the Purchase Orders.
2. Find the PO in question.
3. Open the document
4. Make sure the Qty. to Receive, on the PO Line, equals what was delivered. Make sure any other PO Line that was not received shows 0.
5. Now Post - Receive the PO. If you have the Invoice, you can enter the Invoice Number and Document Date. If yes, you can do both Post - Receive and Invoice.
Hope this helps.
Thanks,
Steve