What is the documents needed to accept any invoice to make the entry in AP section ?

I think we need documents to be attached as below :-

1) Valid Legal invocie ( I mean all the legal entity written on it and valid as well ).

2) PO or PR issued and signed by the authorized person for that.

3)D.T. or Material received or service received in order to amke sure the Goods or service finished.

Finally i MUST mattach all the above to make sure if there are any difference in the3 doucments and MUST inform the supplier offical by mail or fax in order we both agree about any deductions when we both reconile the SOA.