Ah, the invoice: a document that has evolved over the years from the humble handwritten sales slip to an electronic document, routinely sent via email. But even digital invoicing on the Web is in a constant state of change. If you think you know all there is to know about the prospect, think again. If you are getting paid late – two weeks, a month, even a quarter after the bill is due – then this article is for you. To help you get paid in a more timely fashion, here are six tips designed to help you do just that – get your invoices paid in full, on time, every time.  Let's dive right in!