How to send an invoice by email and get paid faster

Published Monday 20 April 2026

Table of contents

• What to include on an invoice
• How to create an invoice
• When to send an invoice
• How to send an invoice
• How to write an invoice email
• What to do when invoices are ignored
• Automate your invoice reminders
• Get paid faster with professional invoicing
• FAQs on sending invoices

Key takeaways

• Include all required details on every invoice, such as a unique invoice number, your business and client details, a clear description of goods or services, the due date, and the total amount including GST, to meet legal requirements and get paid faster.
• Send your invoice by email as soon as the work is complete, as email delivers it instantly, costs less than postal mail, and creates a clear record that you sent it.
• Follow up the day after an invoice becomes overdue, since clients pay nearly 50% of invoices late, and acting quickly stops late payments from becoming a habit.
• Use invoicing software to automate payment reminders, track invoice status, and match payments to outstanding invoices, so you save time and stay consistent without chasing clients manually.

What to include on an invoice

A professional invoice includes your business details, your client's details (which's required to show the buyer's identity for sales of $1,000 or more), a description of what you provided, and the total amount owed. Including these elements helps you meet legal requirements and get paid faster.

Make sure every invoice has:

• the word 'invoice' displayed clearly
• a unique invoice number for your records, which must be kept for at least seven years
• your business name and contact details
• your client's name and contact details
• the date you sent the invoice
• the payment due date
• a clear description of the goods or services provided
• the total amount due, including GST. You can show GST separately or include a statement that 'Total price includes GST'

How to create an invoice

To create an invoice, start with a template and add your business details, transaction information, and payment instructions. This ensures your invoice is complete and professional.

Include these required elements:

Business information

Add these details to identify both parties in the transaction:

• your business name, address, and contact details
• your customer's name and billing address

Transaction details

Record what you're billing for and when:

• a unique invoice number and date
• a description of goods or services provided
• itemised costs and applicable taxes

Payment instructions

Make it easy for your customer to pay:

• the due date
• accepted payment methods
• where to send payment

Learn more in our guide on how to make an invoice.

When to send an invoice

Send your invoice as soon as the work's complete. The faster you invoice, the faster you get paid, keeping in mind you're legally required to provide one within 28 days if requested by a customer. Delayed invoicing leads to delayed payments and cash flow gaps.

Common invoicing schedules include:

• Upon completion: best for one-off projects and services
• Weekly billing: best for improving cash flow consistency
• Monthly recurring: best for retainers and subscriptions
• Milestone billing: best for large projects with completion stages

Tip for steadier cash flow

Spread your invoice dates throughout the month rather than sending them all at once. This helps create consistent income instead of payment peaks and valleys.

How to send an invoice

Email is the fastest and most reliable way to send an invoice. Your customer receives it instantly, and you have a clear record that you sent it.

Email is also cheaper. Processing paper invoices can cost up to $30, while e-invoicing can reduce this to less than $10 according to the ATO.

Best practices for email invoicing:

• Verify the recipient: double-check you're sending to the correct contact
• Use secure formats: send as a PDF or an online link to help prevent fraud
• Follow up on first invoices: call to confirm receipt and understanding
• Enable online payment: include payment links for immediate processing

Australia has adopted the international Pan-European Public Procurement Online (Peppol) framework as its common e-invoicing standard for secure digital invoicing.

Why email works better than postal mail:

• Faster delivery: takes minutes instead of days
• Fewer lost invoices: creates a clear paper trail
• Lower costs: requires no printing or postage
• Delivery confirmation: you know when you sent it and when they received it

Learn more about how online payment services help you get paid faster.

How to write an invoice email

Keep your invoice email short and professional. Include the invoice number, amount, and due date. A clear subject line helps your invoice get processed quickly.

Effective subject line format

Your subject line is the first thing recipients see, so make it count. Use this format for your subject line:

"Invoice [number] - [Company name] - Due [date]"

Include the purchase order number if your customer's provided one.

Simple email template

Use this template as a starting point for your invoice emails.

"Hi [Name],

Please find attached invoice [number] from [your company], due on [date].

You can pay via [payment methods].

Thanks for your business.

[Your name]"

What to do when invoices are ignored

Follow up the day after an invoice becomes overdue. Quick action prevents late payments from becoming a habit. Clients pay nearly 50% of invoices late, so prompt follow-up is essential.

Pre-overdue reminder (one day before):

"Hi [Name], invoice [number] is due tomorrow. Please let me know if you need anything to process payment."

Overdue notice (one to three days late):

"Invoice [number] was due on [date]. When can you make payment?"

Phone follow-up strategy:

• State the overdue invoice number and amount
• Ask when they'll make payment
• Stay silent after asking to let them respond
• Wait for a clear answer or commitment

Quick action prevents late payment patterns from forming and shows you're serious about your payment terms.

Automate your invoice reminders

Automated systems remind customers about invoices by sending follow-up emails on your behalf without any manual effort. You only need to step in for invoices that require personal attention.

You can use Xero's online invoicing software to handle this automatically.

How automation works:

• Tracks all invoices: monitors payment status automatically
• Matches payments: links bank deposits to outstanding invoices
• Sends reminders: delivers pre-written emails on due dates
• Escalates problems: flags invoices that need personal attention

Benefits of automation:

• Reduces stress: you no longer need to emotionally chase payments
• Improves consistency: ensures follow-ups happen on time
• Stays professional: maintains a consistent tone in all communications
• Saves time: frees you up for core business activities

Get paid faster with professional invoicing

Professional invoices help you get paid on time. Use the practices in this guide to protect your cash flow and build trust with customers.

Online invoicing software makes this easier by automating reminders and giving customers convenient payment options.

FAQs on sending invoices

Here are answers to common questions about sending invoices.

How quickly should I send an invoice?

Send your invoice as soon as you complete the work. The faster you invoice, the faster you get paid. You're legally required to provide an invoice within 28 days if a customer requests one.

What's the best way to send an invoice?

Email is the fastest and most reliable method. Your customer receives it instantly, you have a clear record, and it costs less than postal mail. Processing paper invoices can cost up to $30, while e-invoicing reduces this to less than $10.

When should I follow up on an overdue invoice?

Follow up the day after an invoice becomes overdue. Quick action prevents late payments from becoming a habit and shows you're serious about your payment terms.

Can I automate invoice reminders?

Yes. Automated systems send follow-up emails on your behalf, track payment status, and flag invoices that need personal attention. This saves time and ensures consistent follow-ups.

What must I include on an invoice?

Your invoice must include the word 'invoice', a unique invoice number, your business details, your client's details, the date, payment due date, description of goods or services, and the total amount including GST.