Paypal invoice help!!!?

So I'm buying something online from a seller on dhgate, and he sent me an invoice on paypal, and I don't know where I can find it, I know this may seem rather stupid and fake, but I'm seriously lost, isn't the invoice he sent supposed to come onto my recent transactions or transactions stuff, can't find any tutorials. And I'm stuck, if you had a prior usage on paypal, please help me out with this. I wanted to buy a present for my friend, and it's not showing up (the invoice). Thanks in advance if you can help me :)