How to Send an Invoice as a PDF (Professionally)

Send invoices as PDFs that look professional, get paid faster, and don't make you the difficult freelancer.

4 min readConvert to PDF

Project's complete. You email an invoice. Three weeks later it's still unpaid. The client says they never received it. You re-send. Two weeks more.

Invoice quality matters more than freelancers think. Polished invoices get paid faster.

Use a maintained template

Build an invoice template in Word, your accounting software, or a dedicated invoice tool. Include: your name and contact, invoice number, date, due date, client name and address, line items with descriptions and amounts, total, payment terms, and bank details. Convert to PDF for delivery.

Naming conventions

Name the file with the invoice number and client: `INV-0142_AcmeCo.pdf`. Sortable for your records, identifiable for the client. The client's accounts team will tag and file based on the filename — make their job easy and you get paid faster.

Clear due dates

Net 30 is conventional but not mandatory. Whatever you choose, state it clearly on the invoice ("Payment due by 15 April 2026"). For repeat clients, agree terms in the original contract and reference them on each invoice. Vague terms are slow payments.

Chasing without being difficult

Send a friendly reminder a week after the due date. Resend the same PDF, attach a short note ("Just checking this didn't slip through — please let me know if you need anything to process"). Most overdue invoices are oversights, not refusals. The friendly chase works better than the threatening one.

FAQ

Should I include VAT on the invoice?

If you're VAT registered, yes — invoices must show VAT separately. If you're not registered, a clear note ("Not VAT registered") avoids questions.

What payment terms should freelancers use?

Net 14 or Net 30 are conventional. Longer terms reduce your cashflow; shorter terms feel pushy unless agreed in advance.

Can I include late fees?

Yes, but only if specified in the contract and proportionate. UK statutory interest rates apply by default unless contract states otherwise.

Should invoices be password-protected?

Usually no — invoices are routine business documents. Protection adds friction that delays payment.

Polished invoices get paid faster. Convert from your template in Flint and the chase stops being a weekly task.

Try it now

Drop a PDF in and you'll be done in seconds — no install, files private to your account.

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How to Send an Invoice as a PDF | Flint — Flint PDF