Send the invoice before payment, not after
An invoice is a request for payment, so it goes out before the customer pays—not after. You send it to tell someone what they owe, how much, and where to send the money. Once they pay, the invoice becomes a record of the transaction, but the payment itself is the response to the invoice, not the other way around.
The timing matters because an invoice without payment is an open debt. A paid invoice is a closed one. If you send an invoice after someone has already paid you, you are creating confusion about whether the debt is settled, and you lose the paper trail that shows when you asked for the money and when they actually sent it.
Key Takeaways
- Send the invoice before you expect payment so the customer knows what they owe and where to send it.
- A paid invoice is proof the debt is settled; an unpaid invoice is proof it is still open.
- If payment arrives before the invoice, send the invoice immediately after to document what was paid and close the record.
- For recurring work or subscriptions, send the invoice on the same day every month or billing cycle so payment timing stays predictable.
- Keep copies of both the invoice and proof of payment (receipt, bank record, or payment confirmation) for your records.
What happens if payment arrives before the invoice
Sometimes a customer pays before you have sent them an invoice—they might have called in an order, sent a deposit, or paid through a payment link without a formal invoice attached. In this case, send the invoice right away, even though the money is already in your account. The invoice now serves as documentation of what was paid and confirms the debt is closed.
Mark this invoice clearly as paid, include the payment date and method (check number, bank transfer reference, credit card last four digits), and file it with your payment records. This protects you if there is ever a dispute about whether the transaction was completed.
The difference between invoices and receipts
An invoice is a bill you send before or at the time of a sale, asking for payment. A receipt is proof that payment was received. Some businesses send both: the invoice goes out first, and once payment clears, a receipt goes back to the customer confirming the transaction is complete.
For small transactions or point-of-sale sales (a customer buying something in person or online and paying immediately), you may only send a receipt. For larger jobs, retainers, or ongoing services, you send an invoice first, then a receipt or payment confirmation after the money arrives. The invoice is the demand; the receipt is the proof.
Invoicing for work that spans multiple payments
If a customer is paying you in installments—a deposit upfront, then the balance after delivery—send an invoice for the full amount at the start, then mark which portions have been paid as each payment arrives. This keeps the full scope of the debt visible and shows which parts are still outstanding.
Alternatively, send separate invoices for each installment: one for the deposit due before work begins, another for the final balance due on completion. This is clearer for the customer and makes it easier to track which invoice corresponds to which payment. Choose whichever method your customer prefers and stick with it so there is no confusion about what is owed.
When to send invoices for services rendered over time
For ongoing work—a contractor billing monthly, a consultant charging by the hour, a subscription service—send the invoice at the start of the billing period or immediately after the work is complete, depending on your agreement with the customer. Most businesses invoice at the end of the month for work done that month, then give the customer 15 to 30 days to pay.
If you have a contract that specifies payment terms (for example, "net 30" means payment is due 30 days after the invoice date), include those terms on every invoice so the customer knows the deadline. Send the invoice on the same day each month so the customer can budget for it and you can track late payments consistently.
How to handle late or missing invoices
If a customer says they never received an invoice, resend it immediately with a note that this is a duplicate. Keep a record of the original send date and the resend date. If payment is now late, include a statement on the resend that payment was due on [original date] and is now overdue.
If you discover you forgot to send an invoice for work you completed, send it as soon as you remember, even if weeks have passed. Explain briefly that this is for work completed on [date], and include the original work date on the invoice so there is no question about when the service was provided. The customer may push back on paying for old work, but you have documentation that the work was done and you did not bill for it at the time.
Digital invoices, email, and proof of delivery
Send invoices by email or through an invoicing platform (QuickBooks, FreshBooks, Wave, or similar) so you have a record that it was sent. If you print and mail an invoice, keep a copy for yourself. Do not rely on verbal agreements or text messages as proof you requested payment—the invoice is the legal record.
If a customer disputes whether they received an invoice, an email with a read receipt or a platform notification showing delivery is proof you sent it. This matters if the debt goes to collections or if you end up in small claims court over the unpaid amount.
Frequently Asked Questions
Can I send an invoice after the customer has already paid?
Yes, but do it immediately. Mark it as paid and include the payment date and method. This documents what was paid and closes the record. Sending an invoice weeks after payment creates confusion about whether the debt is still open.
What should I do if a customer pays a different amount than the invoice?
Contact them right away to clarify. They may have deducted a discount, applied a credit, or made a partial payment. Send a revised invoice showing what was paid and what remains due, or send a receipt confirming the full amount was received if the discrepancy was intentional.
Do I need to send an invoice if the customer paid by credit card on my website?
Not always. If your payment processor (Stripe, Square, PayPal) sends an automatic receipt, that may be enough. But if you provide a service or ship a product, sending a formal invoice with itemized details helps the customer track what they paid for and gives you a clear record for your books.
What if I invoice someone and they never pay?
Send a reminder email 5 to 10 days after the due date, then follow up again at 30 days past due. After that, decide whether to pursue collection (small claims court, collection agency, or writing it off as a loss). The invoice is your proof the debt exists and when you requested payment.
Should I invoice before or after a customer signs a contract?
Send the invoice after the contract is signed. The contract sets the terms; the invoice is the bill. If payment is due upfront (a deposit), send the invoice the same day the contract is signed so the customer knows exactly what to pay and where to send it.