How to invoice clients: a simple guide for freelancers and contractors

What to include on every invoice

A professional invoice needs to have the right information so your client knows exactly what they owe and how to pay it. Here is what every invoice should include:

• Your business name and contact information - name, address, email, and phone number
• Your client's name and address - who you are billing
• Invoice number - a unique number for every invoice so you and your client can reference it easily
• Invoice date - the date the invoice was issued
• Due date - when you expect payment (common terms are Net 15 or Net 30)
• Line items - a description of each service or product, the quantity, the unit price, and the total
• Subtotal, tax, and total - clearly broken out so there are no surprises
• Payment instructions - how you want to be paid (bank transfer, PayPal, Stripe, e-transfer)

When to send an invoice

The best time to send an invoice is immediately after completing the work. The longer you wait, the longer you wait to get paid. A few guidelines:

• For project work, send the invoice the same day you deliver
• For ongoing or hourly work, send at the end of each week or month
• For large projects, consider a deposit invoice upfront and a final invoice on completion

Do not wait until the end of the month to batch all your invoices. Send each one as soon as the work is done.

How to send an invoice

There are a few ways to get your invoice to your client:

• Email with PDF attached - the most common and professional method. Send the PDF directly from InvoicePrepper.
• Download and hand over in person - for jobs where you are on site. Print it or show it on your phone.
• Share a link - useful when your client prefers not to receive attachments

Always include a short note in your email referencing the job and the invoice number. Keep it brief. Something like: "Hi Sarah, please find the invoice for the electrical work completed on April 3. Let me know if you have any questions."

How to follow up on unpaid invoices

Late payments are common. Most of the time it is not intentional. A polite follow-up is usually all it takes.

1. Day 1 after due date - send a short, friendly reminder. Assume it slipped through. "Just following up on invoice #INV-000042, due April 15. Let me know if you need anything."
2. One week late - follow up again, slightly more direct. Reference the original invoice and the amount owed.
3. Two weeks late - call if you have a number. An email is easy to ignore. A phone call is harder.
4. One month late - send a formal overdue notice. Consider pausing any ongoing work until the invoice is settled.

Common invoicing mistakes to avoid

• Vague descriptions - "consulting" or "work done" is not enough. Be specific about what you delivered.
• No due date - without a due date, clients have no urgency to pay. Always include one.
• Wrong client details - double-check the name and address before sending. Errors slow down payment.
• Not keeping records - track every invoice you send and mark it paid when the money comes in. You need this for taxes.
• Waiting too long to follow up - the longer you wait, the harder it gets. Follow up the day after the due date.

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The fastest way to send your first invoice

InvoicePrepper handles the formatting, numbering, PDF generation, and sending for you. Type your invoice details and your client gets a clean professional PDF. Voice AI is available on the Voice AI plan for hands-free invoice entry.

The free plan includes unlimited invoices and PDF download. No credit card required.