Purchase order, account payable

ok, let me try to explain the problem i have. I make Purchase order, fine, then I copy it to Purchase Invoice. First of all on the Purchase Invoice i am missing the reference to the Purchase Order number

secondly, seem bigger issue is. Then f.e. I need to pay to supplier and choose spend money. So now in Account info, only can see Purchase Invoice #

i think there should be the Purchase order number, right? but its not there. So i try some issue on found out following. When i put in Invoice in the field “Reference” my Purchase Order number, then i can see this number after i choose “spend money” So i think there is something wrong, hope you understand. I guess same issue will be on Sales order, Invoice and so on

You should enter in Reference field invoice number as given by your supplier on their invoice to you.