A guide to e-invoicing for accountants and bookkeepers

Published Thursday 9 July 2026

Table of contents

• How e-invoicing works
• The e-invoicing process
• Singapore's GST InvoiceNow requirement
• E-invoicing requirements around the world
• E-invoicing benefits for your practice and clients
• How Xero supports e-invoicing
• Streamline your clients' invoicing with Xero
• FAQs on e-invoicing

Key takeaways

• E-invoicing lets businesses exchange invoices directly between accounting systems via secure networks like Peppol, cutting manual data entry and speeding up payment cycles for your clients.
• Singapore's GST InvoiceNow requirement is rolling out in phases from November 2025, with full coverage expected by April 2031. Preparing clients now gives your practice a head start on compliance advisory.
• Even where e-invoicing isn't yet mandatory, adopting it early can reduce admin time, improve cash flow visibility, and position your practice as a forward-thinking advisory partner.
• Xero connects to the Peppol network so you can send and receive e-invoices for your practice and clients from within one platform, without additional software.

How e-invoicing works

E-invoicing allows businesses to send and receive invoices digitally between accounting systems, without relying on paper, email attachments, or manual data entry. Unlike a PDF sent by email, an e-invoice travels via a secure network and lands directly in the recipient's software, with transaction details already populated.

For your clients, this means less time spent downloading, re-keying, and reconciling invoice data. For your practice, it means fewer queries about mismatched figures and more time for higher-value advisory work.

The global Peppol e-invoicing network underpins e-invoicing in Singapore, Australia, New Zealand, and much of Europe. Because Peppol is an open standard, your clients don't need to use the same accounting software as their suppliers or customers. As long as both parties are connected to the network, e-invoices flow between systems automatically.

What sets e-invoicing apart from digital invoicing

It's worth distinguishing e-invoicing from standard digital invoicing. Digital invoicing typically involves creating an invoice in software and emailing it as a PDF. The recipient still needs to open, review, and manually enter the data into their own system.

E-invoicing goes further. The invoice data is structured in a standardised format and transmitted system-to-system. The recipient's accounting software captures the transaction details automatically, so there's no manual handling at either end.

The e-invoicing process

Regardless of which software your clients use, the e-invoicing process follows the same core steps.

• Invoice creation. Your client drafts the invoice in their accounting software. The data is structured in a standardised format so it can be read by the recipient's system.
• Network transmission. The e-invoice is sent via a secure network such as Peppol. The network routes the invoice to the correct recipient using their unique identifier.
• Automated data capture. The e-invoice arrives in the recipient's accounting software as a draft bill, with all transaction details pre-populated. There's no need to manually upload or re-key information.
• Audit trail. Every e-invoice creates a clear digital record, making it straightforward to trace transactions, verify payments, and support compliance requirements.

Your clients can register for InvoiceNow and start using e-invoicing today, even before it becomes mandatory for their business. Early adoption gives them time to test the process and resolve any setup issues before compliance deadlines apply.

Singapore's GST InvoiceNow requirement

The Inland Revenue Authority of Singapore (IRAS) is introducing a phased GST InvoiceNow requirement that will eventually cover all GST-registered businesses. InvoiceNow is Singapore's nationwide e-invoicing network, built on the Peppol standard.

For your practice, this represents both a compliance obligation and an advisory opportunity. Clients will need guidance on registration, software readiness, and process changes well ahead of their applicable deadline.

InvoiceNow mandate timeline

The GST InvoiceNow requirement is rolling out in phases based on registration type and annual supply value.

• Before mandatory deadlines: all GST-registered businesses are encouraged to adopt InvoiceNow voluntarily
• 1 November 2025: mandatory for newly incorporated businesses that voluntarily register for GST
• 1 April 2026: mandatory for all new voluntary GST registrants
• 1 April 2028: mandatory for new compulsory registrants and existing businesses with annual supply up to S$200,000
• 1 April 2029 to 1 April 2031: phased rollout for remaining GST-registered businesses, with full coverage by April 2031

Check the IRAS GST InvoiceNow page for the most current timeline, as dates and thresholds may be updated.

How to prepare your clients

Getting clients ready for InvoiceNow involves both technical setup and process changes. The earlier you start, the more time you'll have to resolve issues before compliance deadlines.

• Identify which clients are GST-registered and map them to the relevant mandate phase based on their registration type and revenue
• Register each client for InvoiceNow through the Peppol network, obtaining their unique Peppol identifier
• Confirm their accounting software connects to the Peppol network, or help them move to a solution that does
• Run test e-invoices to verify that data flows correctly between systems
• Update your practice workflows to handle e-invoices as part of regular bookkeeping and GST return preparation

Building this capability into your practice now positions you to offer InvoiceNow readiness as a service, whether that's a one-off setup engagement or ongoing compliance support.

E-invoicing requirements around the world

If your clients trade internationally, understanding how e-invoicing works in other jurisdictions can help you advise them on cross-border compliance. Different countries use different models, and the landscape is shifting quickly.

Common e-invoicing models

Most jurisdictions follow 1 of 3 approaches to e-invoicing.

• Network-based model. Businesses connect to a shared e-invoicing network like Peppol. Different accounting systems can exchange invoices as long as both parties are on the same network. Singapore, Australia, and New Zealand use this model.
• Tax authority validation model. E-invoices must be validated by the tax authority before or shortly after being sent. This gives authorities real-time visibility over transactions. Brazil and Mexico operate under this model.
• Direct exchange model. Businesses send e-invoices directly to each other without routing through a central network or authority. This offers flexibility but requires strong internal record-keeping.

E-invoicing and tax compliance

E-invoicing supports tax compliance by creating a fully digital, tamper-resistant record of every transaction. For jurisdictions that require tax authority validation, e-invoices give agencies near-real-time visibility, reducing the risk of fraud and simplifying audits.

Belgium, for example, made business-to-business (B2B) e-invoicing mandatory from 1 January 2026. The UK-Singapore Digital Economy Agreement (DEA), signed in February 2022, includes provisions for paperless trading and secure cross-border data flows, signalling that e-invoicing will continue to play a growing role in international trade.

E-invoicing benefits for your practice and clients

Beyond compliance, e-invoicing offers practical advantages for both your practice operations and the advisory services you provide to clients.

Shorten the cash flow cycle

E-invoices arrive in the recipient's accounting software within seconds. There's no delay from downloading attachments, re-keying data, or chasing missing details. Your clients' customers can see exactly what's owed and process payment faster.

Because e-invoices use structured data, there's less back-and-forth between clients and their customers to clarify invoice details. This can meaningfully reduce the time between issuing an invoice and receiving payment, giving your clients better cash flow visibility.

Reduce admin time

With e-invoicing, incoming invoices appear as draft bills in accounting software, with transaction data already filled in. This removes the manual step of opening email attachments, entering figures, and cross-checking for errors.

For your practice, this means less time spent on data entry and invoice processing across your client base. That capacity can be redirected to advisory work, whether that's cash flow forecasting, tax planning, or strategic business guidance.

Support cross-border trade

The Peppol network connects businesses across Singapore, Australia, New Zealand, and much of Europe. For clients who trade internationally, e-invoicing simplifies the exchange of compliant invoices across borders without needing separate processes for each country.

As more countries adopt Peppol or compatible standards, your clients can scale their cross-border invoicing without adding complexity. This is especially relevant for Singapore-based businesses with regional supply chains across Southeast Asia and Oceania.

How Xero supports e-invoicing

Xero connects to the Peppol network, so you and your clients can send and receive e-invoices directly from within the platform. There's no need to install additional software or learn a separate system.

Digital records in one place

Xero's e-invoicing feature gives you a single place to manage digital records, track client finances, and prepare GST returns. Because Xero is cloud-based, you can access client records from anywhere with an internet connection.

These records flow into other Xero features and connected apps, so you can use accurate client data to compile reports, prepare tax returns, and help clients plan ahead. When your clients are ready to submit e-invoices, they can do it from within Xero without switching platforms.

Simple to use across practice and clients

Xero gives you and your clients the tools to collaborate in 1 shared workspace. You can give clients individual access so they can see how their business is performing, upload documents, and review financials alongside you.

Automate routine tasks like bank reconciliation and financial reporting so you spend less time on data entry. For clients who aren't ready for e-invoicing yet, Xero also supports digital invoicing and automated payment reminders to help them collect payments on time.

Streamline your clients' invoicing with Xero

E-invoicing is becoming a standard part of how businesses in Singapore manage their finances. With the GST InvoiceNow requirement rolling out in phases, now is the time to build e-invoicing into your practice workflows and start preparing clients for compliance.

Xero connects to the Peppol network and supports InvoiceNow, so you can manage e-invoicing for your practice and clients from a single platform. Combined with tools for practice management, reporting, and collaboration, Xero helps you spend less time on admin and more time on advisory work that grows your practice.

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FAQs on e-invoicing

Here are some frequently asked questions about e-invoicing for accountants and bookkeepers in Singapore.

Is e-invoicing mandatory in Singapore?

Singapore is phasing in a GST InvoiceNow requirement. From November 2025, newly incorporated businesses that voluntarily register for GST must use InvoiceNow. From April 2026, all new voluntary registrants are covered. The mandate expands in stages through April 2031, eventually covering all GST-registered businesses. Check the IRAS website for the latest timeline.

What is InvoiceNow?

InvoiceNow is Singapore's nationwide e-invoicing network, built on the international Peppol standard. It allows businesses to send and receive structured digital invoices directly between accounting systems. IRAS uses InvoiceNow as the foundation for Singapore's GST e-invoicing requirement.

Can my clients use e-invoicing if their suppliers use different accounting software?

Yes. E-invoicing works across different software platforms as long as both parties are connected to the same network. In Singapore, that network is InvoiceNow, which is based on Peppol. Your clients and their suppliers don't need to use the same accounting system to exchange e-invoices.

How do I set up InvoiceNow for my clients?

Start by registering each client on the Peppol network to get their unique identifier. Confirm that their accounting software supports Peppol connectivity, then run a few test e-invoices to verify that data flows correctly. Factor in time to update your practice workflows for handling e-invoices as part of regular bookkeeping.

How does e-invoicing improve my clients' cash flow?

E-invoices arrive in the recipient's accounting software instantly, with all transaction details pre-populated. There's no delay from downloading, re-keying, or querying invoice data. This means your clients' customers can process and pay invoices faster, which can shorten payment cycles and improve cash flow predictability.

What is the difference between e-invoicing and digital invoicing?

Digital invoicing typically involves creating an invoice in software and emailing it as a PDF. The recipient still needs to manually enter the data. E-invoicing goes further by transmitting structured data directly between accounting systems via a secure network, so the recipient's software captures the transaction details automatically.