An invoice moves through four stages once it leaves a supplier: it is issued, verified, approved and paid. Consumer purchases skip the middle two, which is why business payment feels slow to anybody unfamiliar with it. Understanding the two extra stages explains almost every question suppliers ask about where their money is.
Issued and received
The supplier states what was supplied, what is owed and by when, with a unique number and ideally the buyer's order reference. The buyer records when it arrived, because payment terms usually run from that date. An invoice sent to an individual rather than a monitored address enters this stage days late, and the terms have already been running.
Verified
Is it ours, is it new, and does it agree with what was ordered and what arrived. The first two are quick checks against existing records. The third is the match, and it can only run if the order and the goods receipt exist. Where they do not, the invoice needs somebody to investigate it, which is the expensive path.
Approved and paid
Somebody with authority for that spend accepts it, which is recorded with a name, a date and an amount. It is then coded, scheduled into a payment run and paid on the agreed terms, with a remittance advice telling the supplier which invoices the payment covers. That last step removes most of the chasing calls buyers receive.
Questions people ask about how does invoice work
Why is business payment not immediate?
Because it is deferred by agreement and conditional on verification. Paying immediately would skip the check that the goods arrived and the price was right.
What most often delays it?
A missing order reference, arrival at an individual's inbox, and an approver who is unavailable. All three are avoidable.
What can a supplier do to help?
Quote the order reference, bill the address the buyer asked for, and invoice promptly and accurately.