Invoices that get paid

You delivered three weeks ago. You sent something you called an invoice, which was a message with the amount in it. Nothing has happened, your contact has gone quiet, and you're now composing the fourth version of a note that starts "just checking in".

An invoice gets paid when it contains everything the payer's finance system needs to process it without asking you a question. That's the whole mechanism. Every question your invoice provokes costs you one payment cycle, and a payment cycle at most companies is measured in weeks, not days. A $216 wholesale order can sit for six weeks purely because nobody at the other end could work out which budget code it belonged to.

Three fields do most of the work: a unique invoice number, a due date written as an actual date, and payment details precise enough to act on without a follow-up email. Get those right and most of your chasing disappears.

What has to be on it

This is the list. Some of it is legally required where you are, some of it is just what makes the invoice processable, and the invoice doesn't care which is which.

About you. Your legal or trading name, an address, an email, a phone number if you have a business one. If you have a tax registration number, it goes here, and in most of Europe an invoice without one from a registered business is not a valid invoice at all.

About them. Their legal entity name, not the shop's trading name and not your contact's personal name. "Fern & Fig LLC" pays invoices. "Sarah at Fern & Fig" does not, because Sarah isn't in the accounting system.

A unique invoice number. Sequential, never reused, never skipped. This is the field the payer uses to talk to you about the payment, and it's the field their system uses to stop paying the same thing twice. If you've been sending invoices without numbers, that alone is worth fixing this afternoon.

Two dates. The date you issued it, and the date payment is due. Not "net 30". A date.

What they bought. Line by line, with quantity and unit price, described the way they would describe it. "Candles, 24" is worse than "8oz soy candle, Fig & Cedar, 24 units". Their receiving log says the second thing.

The money. Subtotal, any discount, delivery if you charged it, tax as its own line with the rate named, and the total. If your price includes tax, say so and state the tax amount separately anyway, because that's what a tax-registered buyer needs to reclaim it.

How to pay. Bank name, account name, account number, the routing or sort code or IBAN and SWIFT if it crosses a border, and what to put in the reference. Being vague here is the single most common reason a payment arrives untraceable a month later, or doesn't arrive at all.

Their reference. If they gave you a purchase order number, it goes on the invoice in a place a human can see without scrolling.

The three fields that actually decide it

Everything above matters. These three decide.

A number that isn't a name

If your invoice is titled "August invoice" and you send another one in August, you now have two documents with the same identity and a conversation nobody enjoys. Pick a format and stick to it forever: a short prefix and a running number, zero-padded so they sort correctly. INV-0001. Never restart the sequence, not in January, not when you change bank.

A due date, not a convention

"Net 30" is trade shorthand, and different companies count it from different events. From the invoice date, from the delivery date, from the end of the month in which the invoice was received. That last one is common and it turns thirty days into fifty-eight.

Write the actual date. "Payment due 5 September 2026." Then there is nothing to interpret and nothing to argue about, and when you chase it you're pointing at a date rather than at an opinion.

Payment details that survive being copy-pasted

Spell out the account name exactly as the bank has it, including the "Ltd" or "LLC". A payment rejected for a name mismatch bounces back into their system as a failed batch, and failed batches get looked at once a month.

Say what the reference should be, and make it the invoice number. Then when a payment lands, you can match it in three seconds instead of three minutes. If a lot of your money arrives as bare bank credits, the reconciliation problem is the same one every manual rail has, and it's covered in keeping records when you hate paperwork.

Ask the questions before you deliver, not after

This is the part that separates people who get paid on time from people who write follow-up emails.

Before you deliver anything to a company, send one short message and get four answers in writing:

1. Who do invoices go to? Almost never your contact. There's usually an accounts payable address, and an invoice sent only to your contact frequently sits in their inbox for a fortnight before being forwarded.
2. Do you need a purchase order number on it? If they do and it isn't there, their system will reject it silently. You will never be told. You'll find out in week five.
3. What are your payment terms, and when does the clock start?
4. What day is your payment run?

That fourth one is the one nobody asks and it's the most valuable. Most companies pay in batches, on a fixed day, usually weekly or twice a month. An invoice that arrives the day before a run gets paid; one that arrives the day after waits for the next one. Nobody in accounts payable refuses to tell you what day it is, and moving your invoicing to the day before theirs is a free two-week improvement in your cash position for the price of one email.

If you're selling to businesses for the first time and the whole shape is unfamiliar, getting paid by a business not a person covers the wider differences, of which the invoice is only one.

Chasing, in a sequence that keeps the customer

The instinct is to leave it as long as possible so you don't seem difficult. That's backwards. Chasing early, briefly, and without emotion is what professionals do, and companies read it as competence rather than desperation. Chasing late and apologetically is what reads as unusual.

Use a ladder. Escalate on a schedule, not on a mood.

When	Who	What you send
The day before it's due	Accounts payable	One line: invoice INV-0042 is due tomorrow, details below, PDF attached again
3 days overdue	Accounts payable, contact copied	Same message, plus "is there anything missing from it?"
10 days overdue	Your contact directly	Ask them to check it cleared their approval step. Most delays live here
21 days overdue	Phone the AP number	Ask for the payment status by invoice number and the date of the next run
30 days overdue	Written, formal, both	State the amount, the date due, and what happens next. No adjectives

Four things about the wording, which matters more than the timing.

Attach the invoice every single time. Never make them go find it. Half of all "we never received it" is true.

Never ask "did you get my invoice?" That's a yes/no question and yes/no questions get ignored. Ask "is there anything missing from invoice INV-0042 that's holding it up?" That's a question with a job attached, and it routes to somebody who can answer.

Keep it one paragraph and keep the emotion out. The person reading it in accounts payable has never met you and processes hundreds of these. They're not withholding your money; they're working a queue. Being short and specific moves you up the queue. Being wounded does not.

Separate the relationship from the transaction. Your contact at the boutique likes you and has no control over the payment run. Chase the process, stay warm with the person, and say so explicitly if you need to: "totally separate from this, the reorder is boxed and ready whenever you want it."

The message that actually works, at day three, is roughly this:

Hi, invoice INV-0042 for $216 was due on 5 September. I've attached it again in case it's easier. Is there anything missing from it that's holding it up, or a PO number it needs? Happy to reissue in whatever format suits your system.

That's polite, it's specific, it contains the number and the amount, and it offers to do the work. It gets answered.

Late fees, and the honest position on them

Plenty of countries give suppliers a statutory right to charge interest on late commercial payments, sometimes with a fixed recovery fee on top. Whether you have that right, at what rate, and from what date, depends entirely on where you and the customer are. Look yours up before you put a number on an invoice, because a late fee you're not entitled to charge is a line the payer can simply refuse, and it makes the rest of your invoice look amateur.

The practical view: state your terms clearly, including any late fee, on the invoice from the start. Then, in almost every case, don't actually charge it on the first offence. The threat is doing the work. The charge mostly buys you an argument with a company you'd like to sell to again.

Where late fees earn their place is with a repeat offender. Second late payment from the same customer, you apply it, quietly and without a speech. Third, you move them to payment before dispatch and you tell them why in one sentence.

Amara, wholesale candles, Austin

Amara makes soy candles, sells most of them direct at $22, and got her first wholesale order from a boutique in East Austin: 24 units at $9 each. $216.

She sent a message on Instagram with the total and her Venmo. Nothing happened for six weeks. Her contact, the buyer who'd loved the candles at a market, kept saying she'd "pass it on".

What was wrong with it, in order of severity: it had no invoice number, so it couldn't be entered; it went to a person rather than to accounts payable; it had no purchase order number, and the store issues one for every order; it had no due date; and it asked for payment on a personal payment app, which their finance process cannot use at all.

She reissued it as a proper document. Number, the store's legal entity name, the PO number she'd asked for by then, both dates, the line item written the way the store's receiving sheet described it, her bank details with the invoice number as the reference, and her tax ID. It was paid in eleven days.

The second order was 120 units at $8.50, so $1,020, and she did two things differently. She asked for 50% up front before she started pouring, which the store agreed to without blinking, and she timed the balance invoice to land the day before their twice-monthly run. Deposits stop being awkward the moment you ask for them as a normal condition rather than as a favour, and taking a deposit before you start covers how to phrase it so it doesn't read as distrust.

The candles were identical. The difference in how long she waited for her money was about five weeks, and all of it came from fields on a document.

When it's genuinely gone wrong

At around 60 days, stop sending polite reminders, because they've stopped working and you're just training yourself to accept it.

Do these in order. Confirm in writing what was delivered and when, with the delivery evidence attached. Send one formal notice stating the amount, the due date, and the date after which you'll take it further. Stop supplying anything new until it's settled, and say that plainly rather than implying it. Then decide, honestly, whether the amount justifies a formal debt process or a small claims filing in your jurisdiction, because both cost time and one of them costs money.

Most small sellers never get here. The ones who do usually got there because the first invoice had a missing field, the first chase came at week five, and the customer learned that slow was fine.

What Sailo does here, and what it doesn't

Every Sailo order produces an invoice automatically, on every plan including free. It gets a sequential number per shop with a prefix you choose, defaulting to INV-0001 and counting up, and it can't collide with another order's number even if two people check out in the same second. There's a web version at its own link and a PDF download, and the number and link go out in the order confirmation email.

On it: your shop name, location, contact email and tax ID if you've entered one; the buyer's name, email, phone and address; every line with its variant and SKU; the payment method; the payment reference; tracking if you've added it; subtotal, discount with the coupon code, delivery, tax as its own line with the name and rate you set in settings, and the total. Refunds show as their own line. There's a free-text notes field on the shop that prints at the bottom of every invoice, which is the right place for your payment terms, your bank details or a standard note. Free shops carry the Sailo badge on the invoice the same way they do on the shop page.

Now the limitation, and it's a real one. That document is a record of an order that already exists, not a receivables system. There's no due-date field, no payment terms field, no purchase order field, no reminder schedule and no ageing report. It says PAID, PAYMENT SENT, UNPAID or REFUNDED, and it says it because of what you or the payment marked on the order.

So if your business is retail, it's genuinely enough, and it's better than what most small sellers are sending. If you're invoicing companies on thirty-day terms, you'll be building the terms and the due date into the shop-wide notes field by hand, tracking who owes what in your own sheet, and running the chase ladder above from your own calendar. Know that going in rather than discovering it in month three.

For sellers in Germany and much of the EU there's an extra layer, because invoice content is prescribed rather than advisory and getting it wrong has consequences beyond a slow payment. VAT and invoicing anxiety covers what that actually demands.

Do this before you send the next one

Open the last invoice you sent. Check it has a unique number, a real due date, the customer's legal entity name, and bank details someone could pay from without asking you anything. If it's missing any of those, reissue it today with the same number and a note saying "reissued with corrected details", and don't wait for them to ask.

Then send one message to every business customer you have asking who invoices go to, whether they need a PO, and what day their payment run is. Three questions, one message each, maybe fifteen minutes total.

If you're not yet sure what legal details you're supposed to be putting on the thing, do you need to register your business sorts out which of them apply to you.