Knowledge base

How to create and send a sales invoice

Last updated 17/09/2026
Send a customer a bill so you get paid — no accounting knowledge needed.

A sales invoice is the bill you send a customer so they pay you. Send one whenever you've done work or sold something and want to get paid. This guide shows you how to create one in Mighty, check it, and send it.

Before you start

It helps to have two things to hand:

  • Who you're billing — their name, and their email address if you want to send the invoice from Mighty.
  • What you're charging for — a short description and the price. If you charge for your time, that might be "Consulting — March" and a day rate.

Your invoice list

Everything starts from Sales > Sales Invoices. This is where every invoice you've created lives, along with three totals at the top: your sales this financial year, what customers currently owe you, and anything past its due date.

The sales invoice list, with totals at the top and the Create Invoice button at the top right

Draft or approve?

When you save an invoice you have two choices, and it's worth knowing the difference:

  • Save Draft keeps the invoice private. Nothing is sent, and you can change anything. Use this if you're not quite ready.
  • Approve makes the invoice final and gives it its invoice number. This is the version you send to your customer.

Approving doesn't email anything by itself. Once approved, open the invoice and you can send it to your customer by email, or download it as a PDF to send however you like.

What the VAT rate means

If your business is registered for VAT (the tax you add to your prices and pass on to HMRC, the UK tax authority), each invoice line has a VAT rate. Most things use the standard rate of 20%, and Mighty picks that for you. If you're not sure a different rate applies, the standard rate is usually the right choice — and Mighty works out the VAT amount for you either way. If you're not VAT registered, you won't see this field at all.

After you've sent it

Your invoice list shows where each invoice is up to:

StatusWhat it means
DraftNot final yet — your customer hasn't seen it.
OutstandingApproved and waiting to be paid.
PaidThe payment has arrived and been matched to this invoice.

When your customer pays, match the payment to the invoice from your bank screen so Mighty knows it's been paid. The invoice then shows as Paid, and your "currently owed" total goes down.

Common questions

How do I send the invoice to my customer?

Approve it, then open it from the list. From there you can email it to your customer or download a PDF. Adding an email address while you're creating the invoice doesn't send anything — sending is always a separate, deliberate step.

What if I made a mistake?

While an invoice is a draft you can change everything. After you approve it, open the invoice to see what can still be changed. If the invoice was wrong and your customer already has it, the usual fix is a credit note — a document that cancels out some or all of an invoice.

What if my customer hasn't paid?

Invoices past their due date show in the Overdue invoices total at the top of your invoice list, so nothing slips by unnoticed. It's fine to send the invoice again as a reminder.

How to do it in Mighty

Step 1
Open your invoices and select Create Invoice From the menu, choose Sales, then Sales Invoices. Select the blue Create Invoice button at the top right of the list.
Step 2
Choose your customer Pick the customer you're billing from the Customer list. If they're not there yet, select Add and enter their details. Their email goes in the Customer email box — Mighty won't email anything until you choose to send the invoice.
Step 3
Check the dates and add what you're charging for Mighty fills in today's date and a payment due date for you — change either if you need to. Then describe what you sold, the quantity and the price for each line. Select Add new line if you're charging for more than one thing.
Step 4
Save it as a draft, or approve it Select Save Draft to keep working on it later, or Approve when it's ready to send. You can select Preview Invoice first to see exactly what your customer will see.
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