Key takeaways
- Every invoice needs a title, unique number, issue date, your details, the customer's details, line items, totals, currency and payment instructions.
- If you are registered for VAT, GST or sales tax, show your tax number and the tax amount separately.
- Use one unbroken numbering sequence; correct a sent invoice with a credit note, not an edit.
- Write the currency as an ISO code (USD, EUR, GBP, AED) to avoid ambiguity.
- Give a due date, not a vague term.
What every invoice should include
| Field | Why it matters | Common mistake |
|---|---|---|
| Invoice number | Unique reference for both parties' records | Reusing or restarting numbers |
| Issue and due date | Starts the payment clock | No due date at all |
| Seller and buyer details | Identifies the legal parties | Trading name only, no legal entity |
| Line items | Shows exactly what was supplied | A single line reading "services" |
| Tax line | Lets registered customers reclaim tax | Tax hidden inside the total |
| Currency and payment details | Tells the customer how to pay | Bank details missing an IBAN or SWIFT code |
Tax on invoices around the world
Most countries use a consumption tax — VAT in the UK, EU and GCC, GST in India, Australia and Canada, sales tax in parts of the United States. The common thread is that a registered business shows its tax number and the tax amount separately. If you are not registered, issue an invoice with no tax line rather than inventing one.
Country-specific requirements matter: for example, UAE tax invoices show the supplier's TRN and VAT in AED, while Saudi Arabia operates a phased ZATCA e-invoicing framework. See our country guides for detail.
Tax and invoicing rules differ by country and change over time. Confirm current requirements with your accountant or the tax authority where you are registered.
Create an invoice online in five steps
- Open the Invoice Maker and pick a template.
- Add your business details and logo once — they are reused next time.
- Add the customer and the line items.
- Choose the currency and tax rate that apply to you.
- Download the PDF, save it for reuse or send it by email.
Frequently asked questions
Is the DocMak invoice maker free?
Yes. You can create and download invoices free within a fair-use monthly limit. Paid plans raise the limit and add saved templates and team features.
Can I invoice in any currency?
Yes. You can choose from more than 120 ISO currencies and set a default currency in your profile. The amount is shown in the currency you choose; no conversion is applied.
Do I need to add tax to my invoice?
Only if you are registered for VAT, GST or sales tax where you operate. If you are not registered, leave the tax line out.
Can I edit an invoice after sending it?
Best practice is not to. Issue a credit note to cancel or reduce the original, then issue a new invoice with a new number.