Going live with e-invoices at a new foreign-invested company in Vietnam: a set-up plan for the first weeks

A new foreign-invested enterprise (FIE) in Vietnam may not issue a sales invoice until it has registered to use e-invoices and the tax authority has accepted that registration. Registration itself is not hard. What delays go-live is the chain in front of it: a tax code that is active, a digital signature held by someone in Vietnam, an e-tax account, a service provider under contract and a group ERP that can hand data to that provider.

If the first customer shipment is planned for week eight, the invoicing work has to start in week one. This guide sets the steps in the order they depend on each other, notes what each step needs from the foreign parent, and lists the mistakes that most often push the first invoice back — or produce a first invoice that has to be corrected.

Why the order matters

Each step in the Vietnamese e-invoice set-up uses something produced by the step before it. The tax code comes from enterprise registration. The digital signature is issued to that tax code. The e-tax account and the e-invoice registration are both signed with that signature. The service provider can only transmit invoices for a company whose registration has been accepted. A delay at any point moves every later date.

The rules you are working under are Decree 123/2020/ND-CP on invoices and documents, as amended by Decree 70/2025/ND-CP, with Ministry of Finance guidance in Circular 78/2021/TT-BTC. Since 1 July 2026, Decree 254/2026/ND-CP and Circular 91/2026/TT-BTC on e-invoices and electronic documents are also in force. We do not summarise the 2026 texts here; a company registering now should ask its service provider to confirm that the registration forms and invoice formats it uses already follow them.

Before registration: the tax code, the signature and the e-tax account

For a company, the enterprise code on the enterprise registration certificate is also its tax code. Check its status on the tax authority's taxpayer information lookup as soon as it is issued: the name, address and managing tax office shown there are what every invoice will carry, and a typing error found now costs a registration amendment rather than a batch of invoice corrections.

Next comes the digital signature. It is issued to the company's tax code by a licensed certification service provider, either as a physical token or as a remote signing service. Three decisions belong here, not later:

• Who holds it. The signature authorises tax filings and invoices. It should sit with a named person in Vietnam, with a written rule on who may use it and a log of use — not with a regional shared service centre that cannot be reached on a Vietnamese public holiday.
• Whether one signature is enough. Many FIEs use one for tax filings and a separate one, or a remote signing service, for high-volume invoicing through the ERP.
• Renewal. Signatures expire. Put the expiry date in the compliance calendar with a month's margin.

With the signature, the company registers its e-tax account on the tax authority's e-tax portal. This account is where returns are filed and notices arrive, so the registered email address should be a shared finance mailbox, not the personal address of a consultant who helped with incorporation.

Choosing an e-invoice service provider

Most companies issue e-invoices through a service provider that meets the tax authority's conditions and connects to its system. The provider matters more than its price list suggests, because it becomes part of the company's control environment. Questions worth asking before signing:

• Does it offer a documented interface (API) for your ERP, and has it connected that ERP before?
• Can it handle both Vietnamese and English on the invoice layout, with Vietnamese as the governing text?
• How does it store invoices, for how long, and how do you export the full archive — XML files included — if you change provider?
• What happens during an outage on its side or the tax authority's side, and how are delayed invoices transmitted afterwards?
• Who at the provider can see your invoice data, and what does the contract say about confidentiality?

Avoid choosing a provider only because a local accounting firm uses it for all its clients. That may be a fine choice for a small trading company; a manufacturer invoicing hundreds of shipments a month from a group ERP needs a provider that can prove its integration works at volume.

Registering to use e-invoices

The registration is submitted electronically, through the tax authority's e-invoice portal or through the provider's system, and signed with the company's digital signature. It states, among other things, which kind of e-invoice the company will use — in practice, most new FIEs start with e-invoices with a tax authority code, where each invoice is coded by the tax authority before it reaches the buyer — and how the data will be transmitted.

The tax authority responds electronically. Only after acceptance may the company issue invoices. If the registration is rejected, the notice gives the reason; the usual ones are a mismatch between the registration details and the tax registration record, or a signature that does not belong to the company's tax code.

Two points the foreign parent often misses:

1. A dependent branch or second location with its own tax code that will invoice in its own name needs to be set up for that. Decide early which entity invoices which customers; changing it after go-live means changing customer master data and contracts.
2. Changes to registered information — a new address, a new legal name, a change of provider — are notified through the same channel. An FIE that moves from a temporary office to its factory within the first year should expect to do this at least once.

A working timeline for the first weeks

The durations below are planning assumptions from typical projects, not legal deadlines. Replace them with your own once the provider and the ERP team have committed dates.

The test phase is the one most often shortened. Test a price correction, a cancelled order, a foreign-currency invoice and an invoice with more lines than the layout comfortably holds. Each of these fails in some real integrations, and each is far cheaper to fix before the first customer sees it.

The first invoice, and the purchases before it

Choose the first live invoice deliberately: a real transaction with a customer whose tax code you have checked, issued during working hours when the finance lead, the provider and the ERP team are all reachable. Confirm that the tax authority code came back, that the buyer received the invoice, and that the ERP posting, the invoice on the portal and the amount in the sales ledger match.

Purchases start well before sales. From the day the company has a tax code, suppliers should invoice it in its own name and tax code. Common problems in the set-up period:

• Suppliers invoicing the foreign parent, a consultant or an employee instead of the new company. Those invoices do not support the company's input VAT or its deductible costs.
• Costs paid by the parent before the subsidiary existed. These need a clear agreement and supporting documents; they do not become the subsidiary's expenses simply by being recharged.
• Large supplier invoices settled in cash from a petty-cash float. Under Law 48/2024/QH15, a purchase invoice of VND 5 million or more needs evidence of non-cash payment for its input VAT to be credited.

Where to check that the set-up is working

• Taxpayer information lookup — the company's name, address, status and managing tax office as the tax authority holds them.
• The e-invoice portal — whether the registration was accepted, and every invoice issued and received, with its status.
• The company's e-tax account — notices from the tax authority, filed returns and recorded payments.
• The managing tax office — since 1 July 2025 tax administration runs in three tiers: the Tax Department, provincial and city tax offices, and grassroots tax offices (Thuế cơ sở).

After go-live, keep a short monthly routine: invoices on the portal against the ERP sales ledger, received invoices on the portal against accounts payable, and both against the VAT return. The first quarter is when set-up errors show up, and a monthly check finds them while they are still few.