Making payments and getting paid is the mantra of every business. However, for most organizations, financial processes often drain the resources of the business. Did you know that the average employee in a small business spends about 17 hours per month on financial processes alone? This translates to more than two working days on activities unrelated to their hired role.

To keep up, most companies employ invoicing and accounting tools operating on HTML to PDF converters. The upside to a Portable Document Format (PDF) invoices is that they are platform agnostic, secure, and retain formatting across devices.

In this article, we'll discuss how to integrate PDF invoicing functionality within different types of invoicing software. We'll also explore key factors to consider before deciding on the right HTML to PDF Converter API for invoicing tools, and review the PDF invoice creation process offered by the well-known invoicing software platforms.

What Is a PDF Invoice?

A PDF invoice is a template with fillable text fields detailing a financial transaction. These fields may include contact information, an invoice number, payment terms, and a description of goods or services. With PDF invoices,  users can open and review a document without the need to acquire software the original documents were built with.

Why Use a PDF Format Invoice

  • Ease of use. PDF invoices display content—graphics, fonts, formatting—the exact way it was created regardless of the device. With this, you can generate professional invoices without the hassle of misaligned fields.
  • Document integrity. PDF features like digital signatures preserve the integrity of your invoice. Any modification after sealing the document invalidates the signature, indicating tampering.
  • Security. PDF also provides a level of security that prevents unauthorized access. This is possible through the password protection feature.

Types Of Invoicing Tools

There are several invoicing software in the market for businesses of all sizes. Most ​​invoice generators pre-generate invoices--or other documents--in HTML format and do on the flight HTML to PDF conversion whenever a user opens or downloads the document. This is why your invoicing tool must have a high-quality HTML to PDF converter integrated. That said, let's look at some online tools for invoicing and how their PDF invoice generation process looks like.


FreshBooks allows users to download free PDF invoice templates or create one. The latter offers auto-generated invoice numbers, status updates, and an automatic tax calculator.

Here's how to make a PDF invoice on FreshBooks:

  • Open the FreshBooks account and click on Invoice at the upper menu tab
  • Click on the +New Invoice icon
  • Fill in the custom fields. (Business name, email address, product description, payment terms, etc.)
  • Select Save as a Draft, Send by Email or Send as Snail Mail
 Invoicing Tools

Invoice Home

Using this invoice maker, you can create invoices from over 100 free PDF templates. You can also add payment links that allow your customers to pay using credit cards or PayPal.

To make a PDF invoice on Invoice Home from your web browser:

  • Open the tool to access a basic template
  • Click on Switch Document to select the type of invoice you need (tax invoice, proforma, etc.)
  • Click on Select Template to choose from the various options
  • Add a logo or signature through the Select logo and Select Signature buttons
  • Click on Advanced Form to activate a template that has more information (optional)
  • Fill in the required fields for your transaction
  • Click on Save & Continue
  • Download a PDF copy of the invoice or send it by mail.

Invoice Simple

Like with the other tools, you can download a PDF invoice template or create an online invoice. To generate a PDF invoice on this invoice generator:

  • Open the web tool to access a blank invoice template
  • Fill in the fields
  • Add a logo and select a brand color
  • Click on the PDF button at the top of the page to download your PDF invoice.


Invoicebus allows users to create and send unlimited PDF invoices once they sign up. You can also generate PDF invoices from HTML, CSS, and other font files.

Below is how to make a PDF invoice on Invoicebus:

  • Open the invoice maker web page to select a template
  • Fill the required fields
  • Click on the logo field to add yours
  • Select the Download PDF button at the top left side of the page to get a copy

Or, click on the E-mail button on the upper right side to send the invoice as a PDF.

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PDF Invoice Generation: Key Features

As you can see based on the examples of the PDF invoice generation process offered by the main invoicing tools on the market, an invoicing tool must:

  • Provide a number of editable or fillable web templates
  • Support images and styling for branding purposes
  • Provide a Download as PDF or Send as PDF functionality

All of these actually come down to the high-quality automated HTML to PDF conversion, ensuring, among other things, image rendering, broad styling and layout capabilities, and fast processing.

Read our Complete Guide to Formatting Capabilities Your HTML to PDF Converter Should Support.

Developing vs. Buying: What to Consider for Automated PDF Invoice Generation

When building a PDF invoicing tool, you can build your own HTML to PDF converter or consider integrating a PDF Rendering API from a vendor. The right option depends on your business requirements and budget. Before you make that decision, consider the following factors:

  • Financial Cost and Time to Market

Buying any API includes the subscription cost varying based on each vendor. If you opt for a custom tool instead, you'd need to pay for the development. You'd also have to pay for maintenance, upgrades, platform migrations, and associated costs, and you won’t be able to start using your tool until long into the bug-fixing stage. Assess both costs and know what works best for you.

  • Scalability

You have less control over a vendor-based invoicing tool. The software provider oversees the features and upgrades. This could be an advantage because it takes away the hassle of figuring out what's best. But, it could also be a disadvantage because the tool may not reflect your business model or growth. If this option isn't ideal, consider building yours. It gives you 100% control over features, functionality, and upgrades. This way, you can scale the software as your business grows. However, if the software or the feature is not the core of your business, you will have fewer resources allocated to upgrades or improvements. At the same time, the API provider ensures much more frequent updates as they constantly work on improvements.

Automated PDF Invoice Generation
  • Opportunity Cost

This cost varies based on your business. What can the resources spent in building the software add to other areas of your business? How well will the custom software perform vs. a vendor-based tool? Weigh your options carefully.

  • Ongoing support

Building your own PDF conversion feature within your invoicing software puts your business in charge of maintenance. It includes bug fixes, customer support, patches, and security compliance. With third-party software, the vendor would manage these concerns. But you need to consider the quality of support. How fast will they respond to your pressing complaints? How effective are they in resolving issues?

Inkit Render API for At-Scale HTML to PDF Generation Within Invoicing Tools

Generating PDF invoice template HTML in large quantities requires a rending tool. But building one from scratch is an expensive and time-consuming venture. A better option would be to use a pre-built HTML to PDF converter like Inkit Render.

With Inkit Render's robust API, you can automatically convert HTML files to PDF and store them afterward. This software also allows you to send the documents to customers at scale. The best part is that integrating the Render API within your invoicing tool does not require much time or effort.

Here are the basic steps:

  • Sign up for the service
  • Retrieve your key from your dashboard
  • Store the key in a secure place and only grant access to necessary individuals
  • Copy and paste the code into your coding environment
  • Run the snippet to generate your PDF.

Want to try Inkit Render before making a final decision? Sign up for a free plan and start generating PDF invoices from your web portal today.

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