An invoice only gets paid if it is received, read and understood. Between invoices lost in spam folders, blurry photos sent by WhatsApp and messages with no amount or due date, many late payments start at the moment of sending. How you send an invoice affects when it gets paid. Here is good practice for email and for WhatsApp.
Send it the same day
Every day between finishing the job and sending the invoice pushes the payment date back by the same amount. An invoice sent a week after completion will, at best, be paid a week later. Get into the habit of issuing the invoice on site or the same evening.
A short, complete message
The message that goes with the invoice should let the client pay without even opening the document:
- the invoice number;
- the amount due;
- the due date;
- how to pay: payment link, bank details, mobile money number;
- a simple thank you.
Example: "Hello Mrs Mensah, here is invoice INV-2026-0087 for 1,850 for the air conditioning installation. Due on 15 October. You can pay by mobile money or through the link below. Thank you for your business."
Link or PDF?
| Format | Pros | Cons |
|---|---|---|
| Link to the invoice | Viewable on a phone, direct payment, read tracking | Needs a connection |
| PDF attachment | Easy to file and print | No tracking, sometimes blocked or unopened |
| Photo of the invoice | Quick | Hard to read, looks unprofessional |
The best option combines both: a link to view and pay, with the PDF available for the client's records. Avoid photos of paper invoices: they read badly and look careless.
By email: precautions
- A clear subject line: "Invoice INV-2026-0087 – Air conditioning – 1,850".
- A professional sending address, to keep out of spam folders.
- For business clients, send to the accounts address they gave you, with their purchase order number if they have one. See our article on purchase orders.
By WhatsApp: precautions
WhatsApp is often the fastest channel, especially with private clients and in many African markets. The channel does not change the invoice itself: what counts is its content. A few precautions:
- send the link or PDF, never just a screenshot;
- check the client's number, especially if they have several;
- keep a professional tone, even with a client you know well.
Knowing whether it was opened
With a link, you often know whether the invoice has been viewed. That changes how you follow up:
- not opened: simply check the client received it;
- opened but unpaid at the due date: a polite reminder with the payment link.
The follow-up method is in our guide to chasing late payers.
Mistakes that delay payment
- No due date in the message. "Please find attached my invoice" invites the client to pay whenever suits them.
- Invoices batched at the end of the month. A job finished on the 3rd and invoiced on the 30th loses almost four weeks.
- Wrong recipient. In a company, the person who ordered the work is rarely the one who pays it.
- No payment option in the message. Every extra step between reading and paying is a chance to put it off.
- No record of sending. If the client says they never received it, you need the date and channel.
Summary
| Step | Good practice |
|---|---|
| Timing | The day the work is finished |
| Message | Number, amount, due date, how to pay |
| Format | Payment link plus PDF |
| Clear subject, accounts address | |
| Link or PDF, never a photo | |
| Follow-up | Based on whether it was opened |
What the invoice itself must show is covered in our guide to what to put on an invoice, and payment terms in our article on invoice payment terms.