An invoice template in Gmail refers to a pre-designed format that businesses can use to create professional-looking invoices directly within their Gmail accounts. This feature is particularly useful for small businesses, freelancers, and entrepreneurs who rely on Gmail as their primary communication tool and need a simple and convenient way to generate invoices. By utilizing the built-in tools and customizable options available in Gmail, users can streamline their invoicing process, save time, and present a more polished and organized image to their clients.