The 6 Ways You Can Send an Invoice

Invoices serve as the formal documents businesses use to communicate payment details after work, products, services, or billing periods are complete. When you send an invoice, you deliver a payment request along with related transaction details through a chosen communication channel. 

Yet how you send an invoice can directly impact how customers view your professionalism, the clarity of the details, and the overall customer experience. Some businesses rely on simple email attachments, while others require highly automated systems opens in a new tab.

Here are six common invoice delivery methods, along with standard invoicing elements and timing scenarios for professional billing, to help you develop a well-structured approach that supports better recordkeeping and provides clearer payment visibility.

The 6 most common ways businesses send invoices

Once you understand what an invoice is and how to write one, you’ll want to figure out how to send an invoice in the most efficient way. These delivery methods can range from simple, manual communication steps to highly structured digital workflows. 

How a company goes about it often depends on factors like customer expectations, volume, and the maturity of its organization’s document workflow. As they scale, businesses tend to move away from manual, ad hoc methods toward automated solutions to reduce friction.

Here is a look at the most typical approaches organizations use today to request payment securely and efficiently.

1. Email and PDF attachments

Email delivery usually involves sending an invoice as an attachment to the customer’s email address, along with a brief message in the body. This method is more common among freelancers opens in a new tab, consultants, small businesses, and teams managing lower invoice volumes.

Attaching a PDF invoice is popular because the format preserves your layout, brand colors, payment details, and itemization perfectly across any device. A PDF file is also easy for customers to download, store, and forward to other decision-makers.

However, email-based delivery can create visibility challenges. Messages sometimes get lost, attachments can be overlooked, and tracking down related late payments opens in a new tab often requires manual follow-up.

2. Postal mail

Postal mail involves sending a printed, physical document to a customer’s billing address. While the “snail mail” method is less common in today’s digital-first billing, it often still appears in specific industries, legacy customer relationships, or administrative environments where physical documents are expected.

Mailing a paper invoice has clear limitations for growing businesses. Printed documents add significant delivery time, increase printing costs, and require manual handling. Mailing an invoice also provides less immediate visibility into whether the customer actually received or reviewed the request, so it’s a method you see less frequently than the alternatives.

3. Invoicing or accounting software

Invoicing and accounting software enables businesses to create, send, store, and manage invoices in just a few clicks within a dedicated financial system. This method is common for organizations handling recurring invoices, multiple customers, complex tax rates, and detailed accounting workflows.

With the average time to manually process an invoice sitting at just over 10 days opens in a new tab, these systems can deliver built-in value by generating unique invoice numbers, adding payment links, and sending automatic reminders to clients. They also offer robust reporting and tend to integrate smoothly with your broader bookkeeping processes. 

Note that accounting software opens in a new tab generally focuses on financial records and payment collection. In contrast, document workflow tools support the broader communication process around your billing details, client agreements, and related forms.

4. Client portals and payment platforms

Client portals and payment platforms provide customers with a centralized location to view an invoice online, access their billing history, and complete transactions. This method is common in customer relationships, where self-service access, online invoice payment options, and visibility into recurring billing are highly expected.

Portals frequently appear in professional services, software subscriptions, utilities, and other account-based business models. They make it easy for customers to pay immediately with credit or debit cards, electronic payment services, or automated clearing house opens in a new tab (ACH) transfers. 

The main limitation of portal-based invoicing is its reliance on customer adoption. Clients must be willing to log in, remember passwords, and use a separate system to view their accounts.

5. Digital document workflows

Digital document workflows involve preparing, sending, tracking, and managing business documents through a structured digital process. 

This method becomes highly relevant when your invoices connect to a broader set of documentation. For example, your billing might be tied to statements of work, service agreements, approvals, change orders, or payment authorizations. Using a digital workflow lets you manage all these interconnected files efficiently.

Docusign eSignature is a trusted platform for sending and signing business documents electronically when signatures, approvals, or acknowledgments are part of this process. While invoices themselves don’t always require a signature, your broader invoice-related workflows often benefit from consistent invoice templates, secure document delivery, and centralized tracking.

6. Fax machines and digital fax services

Faxing an invoice involves transmitting the billing document over a telephone network to a recipient's physical machine or digital fax service. While this method might seem outdated, faxed invoices are still used in highly regulated sectors such as healthcare, legal, and government. In these environments, legacy billing systems or specific privacy compliance standards often require ongoing faxing of payment requests.

Today, many organizations use cloud faxing rather than physical machines, enabling them to securely send and receive invoice documentation online. Still, traditional faxing typically introduces manual steps, requires ongoing hardware maintenance, and provides limited visibility into when an invoice is actually processed or paid.

What invoice delivery usually includes

Invoice formats vary by business, industry, and billing system, but a professional one typically contains a consistent set of invoice details:

• Sender and customer details: Including the company’s name, the client name, billing address, email address, phone number, and applicable tax information opens in a new tab is standard practice. Adding clear contact details like these ensures the customer knows exactly who to reach if they have questions.

• Invoice identifiers: Adding a unique invoice number and the issue date is common, as is adding a purchase order number, project name, or account number when relevant to the client.

• Goods or services provided: A detailed description or itemized breakdown of the products, services, or hours provided. These line items should clearly explain the deliverables associated with the charge.

• Payment details: The total amount due, taxes, shipping fees, discounts, and specific payment terms. Most invoices also state the due date, accepted payment methods, bank transfer information, and any specific payment instructions.

Providing complete information on your invoices helps both parties understand the transaction, process payments faster, and maintain more accurate records.

Common invoice timing scenarios

Invoice timing varies significantly based on your business model, customer agreements, payment terms, and overall billing process. Here are some common scenarios and how those elements play a significant role.

• After goods or services are delivered: This timing is common in project-based work, completed services, repairs, and one-time product deliveries. Waiting until work is finalized helps you bill accurately for the exact scope of the completed project.

• Before work begins: You’ll often send an early invoice for arrangements involving upfront deposits, retainers, or advanced billing. This secures your cash flow and establishes commitment before you dedicate resources to a client.

• At project milestones: This is a typical approach for larger, long-term projects where billing is tied to specific phases, deliverables, or completion percentages. Breaking up the total cost helps clients manage their budget while keeping your revenue steady throughout the engagement.

• On a recurring schedule: Businesses use this timing for ongoing services, software subscriptions, monthly retainers, or repeat customer relationships. Automating this process helps you receive a reliable income without needing to manually request payment each month.

• According to customer requirements: This scenario is more common in business-to-business opens in a new tab (B2B) relationships where the client has a specific billing cycle, purchase order process, or accounts payable workflow that you must accommodate. Aligning with their internal schedule can help avoid administrative delays.

In the end, delivering a new invoice at the right moment helps maintain healthy cash flow and get paid promptly.

Where digital document workflows fit

Invoices rarely exist in isolation; they live alongside other important business documents, such as initial quotes, statements of work, master service agreements, project approvals, change orders, and customer records. 

Managing all of these files manually can slow down your operations and delay payment collection.

Digital document workflows, like those supported by the Docusign Intelligent Agreement Management (IAM) platform, become most useful when teams need more consistency, visibility, and structure around how these business documents are prepared, sent, reviewed, and stored. For instance, using standardized templates ensures every document you send maintains your professional branding and captures the correct data every time.

While you might not need a customer to sign a standard invoice, related documents often involve formal approval, documented acceptance, or complex routing. You can rely on these platforms as one way to support secure, trackable document delivery when signatures or acknowledgments are part of the broader billing workflow.

Use Docusign’s free invoice templates to help you create polished, professional invoices, and learn more about Docusign eSignature to streamline the way your business sends important documents.