"Are you selling these products in the role as a private person or as a company owner?
Is VAT included in the price?
What percentage vat is paid here in Italy?
Can you please* give me a receipt on what I've bought? (I) would also like the VAT to be stated, thanks.
Can you please* complete this receipt?
Can you please* sign this receipt?"
Efylove,
"please" is not there in the original... but I think it's needed in the English to not sound rude!! If there is any doubts about the bridge, please ask.