Openn Invoice
How to make and send an invoice from your phone
Invoice from the job, not from the desk: making an invoice on a phone in Openn Invoice, sending it from your own WhatsApp or email, recording the payment with a photo, and what to set up once on a computer first.
4 Nov 2026 · 6 min read
Hemi services boilers around Wellington. For years he wrote invoices on Sunday evenings from a notebook of jobs. Half of them were a week old by the time they went out, and a few were never sent at all. Now he makes the invoice in the van before he drives to the next job, and the customer has it before he has left the street. Nothing else about his work changed. The invoices got faster, and so did the payments.
Why invoice from your phone
- It goes out the same day. The day you finish is the day the payment clock starts. See when to send an invoice.
- Nothing is forgotten. The details are fresh: what you did, the parts you used, the extra hour.
- The customer is still there. They can check it with you and ask questions on the spot, not by email a week later.
- Your customers already read their phones. A message with a link is opened sooner than an email with a PDF.
Set up once, on any screen
The things you type only once are easier on a bigger screen. Do these first, on a computer or the phone, and every invoice after that is quick.
| Set up | Why |
|---|---|
| Your business details and tax number | They print on every invoice |
| Your ways to pay: bank details, a payment link | So the customer can pay straight from the invoice |
| Your logo, and your signature or stamp | So the invoice looks like yours |
| The items you sell most, with their prices | So a line is one tap, not typing |
| Your regular customers, with their emails | An email is needed before you can issue |
Making the invoice
Openn Invoice runs in your phone's browser, so there is nothing to install. Sign in, then:
- Choose New invoice.
- Under Bill to, search for the customer and pick them, or choose New customer and add their name and email.
- Check the currency and the due date. Both are filled in for you.
- Under Items, type the item or pick a saved one, then the quantity and the rate. On a phone each line becomes its own small block, so nothing is squeezed.
- Check the Summary. The tax for your country is worked out on every line.
- Choose Save & issue invoice. To finish it later, choose Save as draft.
An issued invoice cannot be edited, so read it once before you issue. If something is wrong afterwards, cancel it or issue a credit note. See cancelling an invoice.
Sending it
On the issued invoice, choose how to send it. In India the first button is Send on WhatsApp. Everywhere else it is Share, which opens your phone's share sheet so you can pick WhatsApp, Messages or any other app. Email opens your own email app, and Copy link copies the invoice link. Each one has the message already written, with the amount, the due date, the link and how to pay. It goes from your own number or address, so the customer knows who it is from. For the etiquette of sending by chat, see sending an invoice on WhatsApp.
When the customer pays
When the money arrives, open the invoice and choose Record payment. Pick how it was paid and the date. You can add a photo of a cheque, a cash slip or a payment screenshot as proof, straight from the camera. The invoice then shows Paid, or Part paid with what is left.
A few habits that help on a phone
- Keep descriptions short. One clear line is easier to type and to read. Details can go in the note.
- Save your common jobs as items. “Boiler service” with its price fills in with one tap.
- Add the site to your home screen from your browser's menu, so it opens like an app.
- Check the customer's email before you leave. A wrong address is the one thing that is hard to fix from the street.
The short version
- Invoicing from your phone means the invoice goes out the day the work is done.
- Set up your details, ways to pay, items and customers once.
- New invoice, pick the customer, add the lines, Save & issue, then send from your own WhatsApp or email.
- Record the payment when it arrives, with a photo as proof if you have one.