What information must be on an invoice?

Every invoice should include your business name and contact details, the client's name and address, a unique invoice number, the invoice date, a due date, a list of products or services with quantities and rates, and the total amount due.

How do I number my invoices?

Use a consistent numbering system — for example, INV-001, INV-002, or a date-based format like 2026-001. Keep numbers sequential so you can easily track outstanding invoices.

What payment terms should I put on an invoice?

Common payment terms include 'Due on receipt', 'Net 14', 'Net 30', or 'Net 60'. Shorter terms improve cash flow. Always state the due date clearly alongside the payment terms.

Do I need to include tax on my invoice?

Whether you charge tax depends on your location and business type. If you are VAT-registered (in the UK/EU), GST-registered (in Australia/Canada), or a US sales-tax collector, you must include the applicable tax rate and amount on every invoice.

Can I send an invoice by email?

Yes — PDF invoices sent by email are standard practice. Attach the PDF and include a brief covering message with the invoice number and amount due. InvoiceDen lets you download a PDF or share it directly from your browser.

How to Write a Professional Invoice (Step by Step) | Invoice Generator Guide

What Is an Invoice?

An invoice is a document you send to a client after delivering goods or services. It tells the client what was delivered, how much they owe, and when payment is due. A well-written invoice gets you paid faster and creates a paper trail for your records.

What to Include on Every Invoice

A professional invoice needs these essential elements:

Your business name and contact details — name, email, phone, and address
Client name and address — the person or company you are billing
Invoice number — a unique identifier (e.g. INV-001)
Invoice date — the date you issued the invoice
Due date — when payment is expected
Line items — a description of each product or service, with quantity and rate
Subtotal, tax, and total — clearly broken out
Payment instructions — how the client should pay (bank transfer, card link, etc.)
Notes — any terms, late-fee policies, or thank-you message

Step-by-Step: How to Write an Invoice

Step 1: Choose a professional template

A clean, readable layout builds trust. Use a template with a clear header, organized line items, and a prominent total. InvoiceDen offers 15 templates across Modern, Clean, and Formal styles.

Step 2: Add your business details

Fill in your name (or business name), email, phone number, and address. If you have a logo, add it — it makes the invoice look more professional and reinforces your brand.

Step 3: Add the client's details

Include the client's full name or company name and their billing address. If you're shipping physical goods, add a separate shipping address.

Step 4: Set the invoice number and dates

Assign a unique invoice number. A simple sequential system (INV-001, INV-002) is fine. Set the invoice date to today and the due date based on your payment terms — 14 or 30 days after the invoice date is standard.

Step 5: List your products or services

Add one line item per product or service. Include a clear description, quantity, and rate. The total for each line is calculated automatically. Keep descriptions specific — "Web design — homepage redesign, 8 hours" is better than "Design work".

Step 6: Add tax, discounts, and totals

Apply the correct tax rate (VAT, GST, or sales tax) if applicable. Add any discount. Review the final total before sending.

Step 7: Write a short note

Use the notes field to say thank you, remind the client of your payment method, or include late-fee terms. Something like: "Thank you for your business. Please transfer payment to [bank details] by [due date]."

Step 8: Download and send

Download the PDF and email it to your client. InvoiceDen generates the PDF entirely in your browser — no data is uploaded to any server.

Common Invoice Mistakes to Avoid

Missing contact details — clients can't pay you if they don't know who you are
No invoice number — you need this for your records and for chasing late payments
Vague line items — be specific so there's no dispute about what was delivered
No due date — "on receipt" is acceptable, but a specific date is better
Wrong tax rate — check your local rules if you charge tax

Getting Paid Faster

Send invoices the same day the work is delivered
Use short payment terms (14 days rather than 30)
Follow up politely if payment is 3 days overdue
Offer multiple payment methods (bank transfer, card, PayPal)
Include a late-fee clause in your notes for clients who habitually pay late