A foreign client says "send your invoice" and you freeze. Do you need a logo? A tax number? Which account details? A vague or incomplete invoice is one of the most common reasons a payment sits in someone's accounts-payable queue for weeks. This guide shows what to put on it, line by line, and how to avoid the mistakes that delay money.
Why the invoice matters more than you think
At small companies, one person may pay you straight from a card or a payment platform. At larger ones, your invoice goes to a finance team that has never met you. They check it against a purchase order or contract, enter it in a system, and approve it. If any field is missing or doesn't match, it gets sent back, and your payment waits for the next cycle.
An invoice is also your record. If a dispute comes up, it shows what you agreed to charge and when you asked for payment. Pair it with a work log and you are well protected.
The essential fields
Every invoice should have these. Nothing here is complicated, but each one has a job.
- The word "Invoice" and a unique invoice number. Use a simple sequence such as INV-001, INV-002. Never reuse a number. Finance teams use it to spot duplicates.
- Issue date and due date. Write dates in a clear format such as 3 December 2026, not 03/12/26, because the US and UK read that differently.
- Your details. Full name exactly as it appears on your bank account or payout profile, business name if you have one, address, email.
- Client details. The legal company name, billing address, and the contact or department the invoice goes to. Ask for these; don't guess from their website.
- Reference. Purchase order number or contract reference, if they gave you one. Many finance teams reject invoices without it.
- Description of work. Specific lines, not "services".
- Quantity, rate and amount per line, then the total.
- Currency. State it once, clearly, for example "All amounts in USD".
- Payment terms. For example "Payable within 14 days of invoice date".
- How to pay you. The exact method and details.
Describe the work so a stranger understands it
Compare two lines. "Web design: $800" tells a finance clerk little. "Homepage and pricing page design, 2 rounds of revisions, delivered 12 November: $800" matches what the manager approved. For hourly work, put the period and hours: "Customer support, 1-15 November, 72 hours at $8/hour: $576".
If your rate and scope came from a contract, copy its wording. Reading the service agreement clause by clause before signing helps you know which wording to mirror, including invoice timing and payment terms.
A worked example (hypothetical)
Say Amaka, a Lagos-based video editor, edits six videos for a UK agency at $60 each and adds a $40 rush fee. Her invoice would read:
| Item | Qty | Rate | Amount |
|---|---|---|---|
| Edit of 6 product videos (batch 3), delivered 18 November | 6 | $60 | $360 |
| Rush turnaround, 48 hours, agreed by email 16 November | 1 | $40 | $40 |
| Total due (USD) | $400 |
Above the table: invoice number INV-004, issued 19 November 2026, due 3 December 2026 (14 days), PO reference from the agency, and her payment details below. Notice the rush fee line points to the email where it was agreed. That removes any argument.
Currency, fees and payment details
Invoice in the currency you agreed, and do not change it midway. If you are paid in dollars but your platform takes fees or converts to naira, that is your cost to plan for, not a line to add after the fact unless your contract says so. Our fee checklist for receiving dollars helps you compare options before you put details on an invoice.
For payment details, include only what's needed for the method you chose: for a platform, the email or username registered there; for a bank transfer, the account name, bank name, account number and any codes the client's bank asks for. Ask the client which details their bank requires, as it varies by country and by route. Double-check every digit. A wrong digit in an account number can cost you weeks.
Who bears transfer fees? Say so if it matters, for example "Client covers sending fees". Many clients assume you'll absorb them unless told otherwise, and some contracts already decide this.
Tax and registration lines
Don't invent a tax ID. If you have a business registration or tax number, you can add it. If you don't, leave it off unless the client asks. Some foreign clients ask for a form, such as a tax declaration for non-residents; ask their finance team what they need and why, rather than guessing. Whether you must register a business or pay tax on foreign income depends on your country and situation, so check with the relevant tax authority or a licensed accountant. Be careful about VAT: don't add VAT to an invoice unless you are registered and an adviser has confirmed it applies.
Sending, following up and getting paid
- Send as a PDF, named clearly: "Invoice INV-004 - Amaka Obi - November 2026.pdf".
- Email it to the right person and copy your manager. Ask who handles billing at the start of the engagement.
- Invoice promptly, on the schedule in your contract.
- Follow up politely a few days before the due date, then the day after. A short note works: "Checking that invoice INV-004 reached your team and whether you need anything else from me."
- Note the payment in your records when it arrives, with the amount actually received.
Keep copies of every invoice and the proof of payment. They are your evidence for tax questions, bank queries and any future income-risk planning.
Common mistakes
- Missing purchase order numbers. Ask early whether one is needed.
- Name mismatch. Your invoice name differs from your bank or platform name, so the payment gets held.
- Vague descriptions that finance can't match to an approved task.
- Changing scope without a paper trail. Extra work should appear on the invoice with a reference to the approval.
- No due date, which leaves payment timing open.
- Using a template with someone else's branding or a copied tax number. Keep it honest and plain.
Frequently asked questions
Do I need special software to invoice?
No. A clean document made in a word processor or a free invoice template, exported as PDF, is enough. Invoicing tools help with numbering and reminders once you have several clients.
Should I invoice before or after the work?
Follow your contract. Common patterns are after delivery, at month end for ongoing work, or part upfront for large projects. For new clients, asking for a deposit is reasonable.
What if the client wants their own invoice format?
Use it. Large companies often have a required form or portal. Fill it in with the same details described above.
Can I charge a late fee?
Only if it is in your contract or agreed in writing beforehand. Adding one afterwards usually causes friction and may not be enforceable.
Your next step
Open a blank document today, build an invoice template with the fields above, and save it as INV-001. Then ask your current or next client one question: "Who receives invoices, and do you need a PO number or any specific details?"
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