There are two different questions hiding inside "what goes on an invoice."
The first is what the CRA requires, which is a matter of regulation and covered in detail in our piece on GST/HST invoice requirements. The second is what actually gets you paid, which is not regulated at all and matters more to your cash flow. This is the second list.
Sounds obvious. It is not always there. An accounts-payable clerk processing forty documents needs to sort yours in under a second, and a header that says Statement of Work or nothing at all gets set aside for later. Later is a place invoices go to die.
Sequential, unique, never reused. 2026-041 beats Invoice for March. Your client's system will likely reject a duplicate number outright, which means an invoice you reissue with a tweak needs a new number or a credit note against the old one. Reusing numbers also makes your own year-end reconciliation harder than it needs to be.
Not the date you did the work. The date the invoice was issued, which is what payment terms count from.
The legal name of the business, not just a logo. If you operate through a corporation, use the corporation's name. If you invoice as Jane Smith Consulting but the cheque needs to be made out to 1234567 Alberta Ltd., say so on the invoice — otherwise you will get a cheque you cannot deposit.
In full, in the format 123456789RT0001. Required above $100, and there is no reason to leave it off below that. If you are not registered, leave it off entirely and charge no tax.
The entity being billed, not your day-to-day contact. Required above $500, and useful below it, because "who is this actually for" is a question that stalls invoices in larger organisations. If your contact is Sarah in marketing but the bill goes to head office, both names belong on the document.
The person approving payment often has no idea what you do. They were not on the call. They are matching your invoice against a purchase order and a budget line. "Consulting — $8,000" tells them nothing and gets forwarded to someone who might know. "Website content audit, 12 pages, delivered 14 August 2026" gets approved. Specific descriptions also satisfy the CRA requirement at the top tier, so this line does double duty.
Subtotal, then tax as its own line with the rate named, then the total. Something like:
Subtotal $3,200.00 GST (5%) $160.00 Total due $3,360.00
Your client's bookkeeper needs the tax separated to claim it. Burying it in a single total creates work for them and delay for you. If you work across provinces, name the right tax: Alberta is 5% GST, Ontario is 13% HST, British Columbia is 5% GST plus provincial sales tax handled separately. Which applies generally depends on where the customer is, not where you are.
This is the single highest-leverage line on the invoice. "Net 30" requires arithmetic. "Payment due by 14 September 2026" does not. A date is harder to postpone than a duration, and it removes any argument about when the clock started.
If you charge interest on overdue amounts, it has to be stated on the invoice to be enforceable in practice. Something plain works: Accounts unpaid after 30 days are subject to interest at 1.5% per month.
You would be surprised how often this is missing. E-transfer address, banking details for direct deposit, or a link to pay by card. If you accept several methods, list them. Every extra step between wanting to pay you and being able to pay you is a delay, and some of those delays last weeks. A "Pay now" link that opens a card payment page is the shortest distance between the two.
If your client gave you a PO number, it goes on the invoice. Many larger organisations will not process an invoice without one, and nobody will tell you that — the invoice simply sits. Ask for the PO number before you start work, not after you send the bill.
Send it the day the work finishes. Invoices sent within 24 hours get paid measurably faster, mostly because the work is still fresh in the approver's mind and nobody has to reconstruct what happened three weeks ago.
Send it to the person who pays, not the person who hired you. They are frequently different people, and the second one has no budget authority and no urgency. Ask early: who should invoices go to?
We built a free Canadian invoice template that includes every field above, calculates GST/HST by province, and exports to PDF. No account, no email required.
If you would rather have invoices, payment reminders and your books in one place, that is what Internoodle does — and the accounting and invoicing side is free forever.