How to Create an Invoice: Complete Step-by-Step Guide
Whether you're invoicing for the first time or want to improve your process, this guide walks you through every step of creating a professional invoice — from the required fields to sending and getting paid.
Add Your Business Details
Start with your business name (or your full name if you're a sole proprietor), physical address, email, phone number, and VAT registration number if applicable. This identifies you as the seller and is required by SARS for tax invoices.
Add Your Client's Details
Include the client's full name or company name, their address, and email. For B2B transactions where both parties are VAT-registered, include their VAT number as well.
Assign an Invoice Number
Every invoice needs a unique, sequential number. Use a consistent format like INV-001, INV-002, etc. This is required for tax compliance and helps both you and your client track payments. Illumi generates these automatically.
Set the Date and Due Date
Include the date the invoice is issued and the date payment is due. Common terms include 'Due on Receipt', 'Net 7' (7 days), 'Net 14', or 'Net 30'. Shorter terms mean faster payment.
List Your Line Items
Describe each product or service provided. Include the quantity, unit price, and total for each line. Be specific — 'Website Design: Homepage + 5 inner pages' is better than 'Design Services'. Clear descriptions reduce disputes.
Calculate Subtotal, Tax, and Total
Add up all line items for the subtotal. If you're VAT-registered, add 15% VAT. Clearly show the subtotal, VAT amount, and grand total. If you're not VAT-registered, just show the total. Illumi calculates all of this automatically.
Add Payment Instructions
Tell the client exactly how to pay. Include your bank name, account number, branch code, and reference to use. Even better — add an online payment link so they can pay by card or EFT with one click.
Send and Track
Send the invoice via email or WhatsApp. Then track whether it's been viewed and whether payment has been received. Follow up promptly if the due date passes. Illumi tracks all of this automatically.
VAT Invoice Requirements in South Africa
If your annual turnover exceeds R1 million, you must register for VAT with SARS. Once registered, your invoices must include:
- The words "Tax Invoice" prominently displayed
- Your VAT registration number
- The date of supply
- A serial number (invoice number)
- Your name, address, and trade name
- The recipient's name and address
- A full description of goods or services supplied
- The quantity of goods or extent of services
- The value of supply, VAT charged, and consideration for the supply
Illumi automatically includes all of these fields when you toggle VAT on in your settings. You don't need to memorise the SARS requirements — we handle it for you.
Common Invoice Mistakes to Avoid
- Missing invoice numbers — Every invoice must have a unique number for tax records
- Vague descriptions — "Services rendered" invites questions and delays payment
- No due date — Without a deadline, clients pay whenever they feel like it
- Wrong calculations — Manual math leads to errors. Use software that calculates automatically
- No payment instructions — Make it obvious how to pay you
The Fastest Way to Create an Invoice
While you can create invoices manually in Word or Excel, it's slow, error-prone, and unprofessional. Modern invoice software like Illumi lets you create a polished invoice in under 60 seconds:
- Select a client (auto-fills their details)
- Add line items with descriptions and amounts
- Review the auto-calculated total
- Click send — done!