Want to know how to write an email with an invoice attached? Read on for our top tips, as well as a sample invoice email you can use for your customers.You'll learn essential tips to write the best invoice emails and provide 6 invoice business email templates and a template for you to use. Use this invoice email template to write and send invoices that are straightforward and easy to understand, making it easier for you to get paid on time. Nevada Free Invoice Templates. Utilize our Invoice Template to formally request payment for your services or work. In this article, we'll outline what you need to include to write a strong invoice email. Need a professional invoice template? We've got you covered.