Freelancers and small business owners routinely overpay for invoicing software. Subscriptions that charge ten to thirty dollars a month for the ability to send a PDF with your name and a number on it are hard to justify when you are just starting out or when you invoice occasionally. A free, professional-looking invoice does not require software: it requires the right tool.
What a professional invoice must include
An invoice that will hold up legally and get paid promptly needs specific information. Missing fields create delays, disputes, and accounting problems on your client's end. Every invoice should include: your business name and contact details, the client's business name and contact details, a unique invoice number, the invoice date, a payment due date, an itemised list of services or products with quantities and unit prices, the subtotal, any applicable taxes with the rate specified, the total amount due, and your payment details (bank account, PayPal, or other accepted methods).
Invoice numbering: why it matters
Invoice numbers are not optional. They serve multiple purposes: they let you track payment status by number, they are referenced in bank transfers when clients pay, they appear in expense reports when clients file them, and they are required for VAT compliance in most jurisdictions. Use a simple sequential format (INV-001, INV-002) or a date-based format (2026-06-001). Whatever you choose, be consistent and never reuse a number even if an invoice is cancelled.
Payment terms: how to set them clearly
- •Net 30: payment due within 30 calendar days of the invoice date. The most common term in B2B transactions.
- •Net 15 or Net 7: shorter terms appropriate for smaller projects or clients with good payment history.
- •Due on receipt: payment expected immediately. Appropriate for one-time services to new clients.
- •50% upfront: for larger projects, require a deposit before starting. Reference this on the final invoice.
- •Late payment penalties: specify the interest rate for overdue invoices (1.5% per month is common). This is legally enforceable in most jurisdictions and motivates timely payment.
Tax considerations
If you are VAT-registered (or GST, HST, or sales-tax registered depending on your country), your invoice must show the tax rate applied and the tax amount separately from the subtotal. In the UK and EU, a VAT invoice must include your VAT registration number. In the US, sales tax requirements vary by state, product type, and whether you have nexus in the buyer's state. If in doubt, consult a local accountant: getting tax on invoices wrong creates problems on both sides.
How to send and follow up on invoices
Send invoices as PDFs, not as editable documents. A PDF cannot be accidentally modified by the recipient, looks professional in any email client, and prints identically on any printer. Email the invoice directly to the person responsible for accounts payable: not just your main contact, who may not handle payments. Follow up one week before the due date with a brief reminder, and on the due date itself if payment has not arrived. A polite, firm follow-up system prevents invoices from sitting forgotten in someone's inbox for months.
What to do when an invoice is disputed
When a client disputes an invoice, respond in writing with a clear explanation of the work covered. Reference your contract or statement of work if you have one. If the dispute is valid, issue a credit note (a formal document that cancels or reduces an existing invoice) and issue a corrected invoice. If the dispute is not valid and payment is refused past a reasonable point, small claims court is an option in most countries for invoices below a threshold (typically a few thousand dollars or pounds) without needing a lawyer.
AlteredIdea's Invoice Generator creates professional PDF invoices with your branding, line items, taxes, and payment terms. Everything is generated in your browser: no account needed, no subscription, no watermarks.