Amazon: Is an invoice sent as a hard copy to the invoice address?

[Jan]

You could be a little more specific and tell us which amazon... .com? .co.uk? .de? .fr?
Every country has their own legal systems which require different things from companies.

That being said, my experience is that amazon usually does send hard copy invoices with the package you receive.
My experience is also that you don't need the invoice because if there's a problem with it, you have your order information online and they're the most friendly company in dealing with returns / warranties / repairs / complaints.

If you need an invoice that wasn't delivered with your package, you can always request a duplicate for free.