What is an e-invoice? A guide for businesses in Vietnam

Understand Vietnam's e-invoicing rules, when to issue invoices, how invoice data reaches the tax authority, and how to choose compliant software.

Electronic invoicing is an important part of doing business in Vietnam. To use e-invoices correctly, businesses need to understand what they are, when invoices must be issued, how to register for their use, and what makes an invoice legally compliant.

This guide explains the essentials under Vietnam's current framework, including Decree 254/2026/NĐ-CP and Circular 91/2026/TT-BTC, both effective from 1 July 2026.

1. What is an e-invoice?

An electronic invoice, or e-invoice, is an invoice created, signed, sent, received and stored as electronic data in accordance with applicable law.

In Vietnam, sellers are generally required to issue e-invoices when selling goods or providing services, except in cases specifically exempted or otherwise treated under the regulations.

An e-invoice is more than a document recording a transaction. It can serve as a basis for tax declarations, accounting records and reconciliation between the seller, buyer and tax authority.

A legally compliant e-invoice must meet the applicable requirements for invoice content, data format, electronic signatures and invoice processing.

2. Who must use e-invoices?

Businesses and other organisations or individuals within the scope of the regulations must register for and use e-invoices as required by law.

For service businesses, an e-invoice is commonly issued when services are supplied or at another legally prescribed time, depending on the nature of the transaction.

There are two main categories:

• E-invoices with a tax authority code: The seller submits the invoice data to the tax authority for coding before sending the coded invoice to the buyer.
• E-invoices without a tax authority code: The invoice is created under the applicable rules, and its data is transmitted to the tax authority according to the required method and deadline.

The applicable category depends on the business, its activities and the relevant regulations. Businesses should confirm which type applies before registering.

3. Is an e-invoice just a PDF?

No. A PDF may be used to display an invoice or send a readable copy to the buyer, but it does not necessarily contain all the data required for a legally compliant e-invoice.

E-invoices must use the prescribed data format. Depending on the invoice type, the underlying data may include an XML file, electronic signature information and a tax authority code where coding is required.

Receiving a PDF alone does not necessarily mean that you have all the data needed to verify the e-invoice.

Businesses should check the invoice details and its processing status using the appropriate system or verification method, rather than relying only on how the file looks.

4. How are e-invoices transmitted to the tax authority?

E-invoices must not only be created in the required format. Their data must also be processed and transmitted to the tax authority in accordance with the applicable rules.

Businesses need an e-invoicing solution that meets the relevant technical requirements and can connect to the tax authority's system, either directly or through a suitable service provider.

The transmission process depends on the invoice type:

• Invoices requiring a tax authority code: The seller submits the invoice data for coding before sending the coded invoice to the buyer.
• Invoices without a tax authority code: Invoice data must be transmitted according to the applicable method and deadline. For standard cases using the full-data transmission method, the deadline may be no later than the next working day after the invoice is issued. Certain invoice types follow separate methods or deadlines.

Not every invoice follows the same transmission process, and not every invoice must receive a tax authority code before it is sent to the buyer. Businesses must follow the requirements applicable to their invoice type.

Which software can be used to issue valid e-invoices?

Not every invoicing tool can issue legally compliant e-invoices in Vietnam. A tool that creates a PDF or an invoice template does not automatically produce a legally valid e-invoice.

Businesses should use a solution that meets current legal and technical requirements, complete the required registration for e-invoice use, and ensure invoices are created, digitally signed, transmitted or coded according to the applicable rules.

Using software that does not meet the requirements, or failing to follow the required registration and invoice-processing procedures, may result in invoices that do not satisfy legal requirements. The fact that software can generate an invoice does not, by itself, make that invoice legally valid.

Check the service provider: Businesses should consult the list of e-invoice service providers published by the tax authority on the General Department of Taxation's official website.

Before choosing a provider, confirm that it supports the invoice type your business needs, transmits data to the tax authority, handles system responses and retains the required records.

5. When must an e-invoice be issued?

The required time for issuing an invoice depends on the transaction and the applicable rules. Businesses should not assume that invoices are always issued at the end of the month or only after the customer has paid.

For many sales of goods, the invoice timing is linked to the transfer of ownership or the right to use the goods, as prescribed by law. For services, the invoice is generally issued when the service is completed, or when payment is received in specific cases where the regulations prescribe that timing.

For example, a design agency providing services to a client must determine the invoice date based on the rules applicable to the service and transaction, not simply the date the client makes a bank transfer.

A quotation, payment request and e-invoice serve different purposes:

• Quotation: Sets out the scope of work, price and service terms.
• Payment request: Tells the customer how much to pay and how to pay it.
• E-invoice: Records the transaction in accordance with invoicing law.

Businesses should determine the correct invoice timing for their transactions and consult their accountant when a specific case is unclear.

6. How do you register to use e-invoices?

Businesses must complete the required registration before using e-invoices.

The exact process varies depending on the invoice type and solution selected, but businesses will generally need to:

1. Choose an appropriate e-invoicing solution. Check its regulatory compliance, supported invoice types, digital-signing capabilities and connection to the tax authority.
2. Prepare business information. Ensure the registered business name, tax identification number, address and representative details are accurate.
3. Register for e-invoice use. Complete the required registration procedure and wait for the relevant outcome.
4. Set up digital signing and invoice details. Configure the information required to create, sign and transmit invoices.
5. Check the process before regular use. Confirm that invoice creation, data transmission, system responses and record retention work as required.

A service provider may guide the business through setup and explain which documents are needed. The specific documents depend on the provider and applicable procedure, so confirm the requirements before submitting an application.

7. Do businesses need a digital signature for e-invoices?

A digital signature or other compliant form of electronic signature is an important part of e-invoicing where required by the applicable rules.

Businesses must ensure that invoices are signed correctly and that the signature can be verified when necessary. Specific requirements may vary depending on the invoice type and any applicable exceptions.

When choosing software, check whether it supports digital signing, certificate management and the required invoice-processing procedures.

Some solutions integrate digital signing into the account, so businesses do not need to configure every component separately. They should still confirm that the solution meets the signature requirements applicable to their situation.

8. What should you do if an e-invoice contains an error?

If an error is found in an e-invoice, the business must follow the procedure applicable to the type of error and the invoice's status. Do not simply delete the invoice or issue a new one without following the required process.

Depending on the circumstances, the invoice may need to be adjusted or replaced, or the business may need to complete the relevant notification or explanation procedure.

When an error is identified, businesses should:

1. Check the incorrect details and the invoice's status.
2. Consult their accountant to determine the appropriate treatment.
3. Make the required adjustment or replacement under the applicable rules.
4. Keep the related invoices and processing records for future reconciliation.

Software that maintains a clear processing history helps business owners and accountants track changes, avoid missing information and review previous actions more easily.

9. Manage quotations, payments and invoices on one platform

Issuing an e-invoice is only one part of managing business finances. Before and after an invoice is created, businesses also need to manage customers, quotations, payments, expenses and accounting information.

When this information is scattered across emails, messages and different tools, businesses can spend time searching for records, re-entering data and reconciling transactions.

Invoi.vn brings business management into one platform, connecting customer and supplier information with quotations, invoices and expenses. Business owners and accountants can work from the same source of information, reducing manual work and the risk of lost records.

With Invoi.vn, businesses can:

• Create professional quotations and manage customer information.
• Issue and manage e-invoices.
• Use integrated HSM digital signing without a separate physical USB Token.
• Track payment information and connect relevant data to invoices.
• Keep business owners and accountants aligned, even when accounting staff change.

Invoi.vn is designed to help businesses manage their operations and financial information more clearly while meeting the applicable requirements for e-invoicing.

10. Frequently asked questions about e-invoices

Are e-invoices mandatory in Vietnam?

Businesses and other taxpayers covered by the regulations must register for and use e-invoices as required by law. The specific obligation depends on the business activity and any applicable exceptions.

Is a PDF a legally valid e-invoice?

Not necessarily. A PDF may be a readable representation of an invoice, but the e-invoice must meet the applicable data and legal-processing requirements. A PDF alone is not enough to establish that an invoice is valid.

Must e-invoices be sent to the tax authority immediately?

Not every invoice follows the same transmission deadline. Invoices requiring a tax authority code must be submitted for coding before the coded invoice is sent to the buyer. For invoices without a code, the transmission method and deadline depend on the applicable rules for that case.

Can I create invoices using Excel or PDF software?

Creating an invoice template or PDF does not mean that you have issued a legally compliant e-invoice. Businesses need a solution that meets the relevant legal and technical requirements and must complete the required registration and invoice-processing procedures.

Do I need a USB Token to digitally sign e-invoices?

Not necessarily. Depending on the solution and type of digital signature, a business may be able to sign electronically without a physical USB Token. Confirm that the chosen solution meets the applicable signing requirements.

Where can I find e-invoice service providers?

Consult the information and provider lists published on the General Department of Taxation's official website. Check the current information and confirm that the solution meets the requirements for the invoice type your business needs.

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Disclaimer: This article provides general information and does not replace legal or tax advice for a specific transaction. Businesses should consult the current regulations and seek guidance from their accountant or tax authority when confirming their obligations.