Email and phone do not appear on the face of the Enterprise Registration Certificate, but they are the company real legal communication lines with the State: file-supplementation notices, registration results, tax reminders and electronic-account authentication all flow through these two channels. The question “is it mandatory” therefore has two answer tiers — mandatory to declare at filing, and operationally vital to maintain.
Mandatory at filing, flexible on the certificate
The enterprise registration file under Decree 168/2025/ND-CP and the national business registration system requires contact information of the company and its representative — including phone number and email address — as part of the registration data; the online registration account and the electronic tax filing account also bind to email and phone for authentication and code delivery. A file missing this contact data in practice cannot complete the electronic registration process. Yet email and phone are not among the contents printed on the ERC nor core registration contents like name, head-office address or charter capital — consequently, changing them does not follow the formal change-registration procedure of an address change.
Handling an email or phone change: the company updates contact information with the business registration authority through the registration system, and synchronises the update across the e-tax filing account, the e-invoice system, the electronic social insurance account and the bank. None of these updates reissues an ERC, but forgetting one system leaves a dead communication channel in the State file.
The legal weight of notices sent to the registered email
Authority notices sent to the registered email and electronic accounts carry real operational weight: registration file amendment and supplementation requests arrive through the business registration system; tax notices, filing reminders and electronic decisions travel through the e-tax transaction account; many authorities treat successful sending to the registered address as completed notification, and response deadlines start running whether or not the company opens the email. This is why the registered email must be a company mailbox checked daily by a responsible person — not the personal mailbox of the staff member who handled formation and later resigned.
Sound governance practice: use a functional mailbox on the company domain (info@, legal@) accessible by at least two people, set a rule forwarding every authority message to the representative and the accountant the same day, and archive notices as legal documents. The registered phone should be a stable office or representative number, not a prepaid SIM used once for the formation round.
Losing the registered email: risk scenario and recovery
Losing control of the registered email — the mailbox holder resigns, the password is forgotten, the domain expires — creates three linked risks: the company misses authority notices (file supplementation, tax notices) and lets deadlines lapse; electronic accounts authenticated by that email fall outside control or, worse, are password-recovered by someone else; and when accounts need recovery, the lost email is itself the default authentication channel, creating an administrative loop. This scenario is common enough that it should be prevented from formation day by the functional-mailbox policy above.
Once lost, the recovery path comprises: contacting the business registration authority and the managing tax authority to update new contact information with papers proving the legal representative authority; running recovery or email-change procedures on each electronic system (business registration, tax, invoices, social insurance, bank) under each system own verification process; and back-checking the loss-of-control period for missed notices — especially time-bound tax notices — to remediate before late-response penalties land.
The registered email and phone are the company legal communication infrastructure — cheap to maintain correctly and expensive to lose. A functional mailbox checked daily, a stable phone number, and one synchronised update round across all systems at every change: that is the whole discipline required. This draft is pending review by the QA Council.
Frequently asked questions
Are email and phone mandatory in enterprise registration?
Yes at file level: enterprise registration data under Decree 168/2025/ND-CP and the online registration process require the phone number and email of the company and its representative, and electronic accounts (registration, tax filing) use email and phone for authentication. But these data are not printed on the ERC and are not core registration contents like name or head-office address, so changing them is not a certificate-reissuing change-registration procedure.
Must an email change be notified?
Yes, as a contact-information update on the business registration system and — more importantly — synchronised across every electronic system using that email: the tax filing account, e-invoices, electronic social insurance and the bank. Without synchronisation, each authority notices keep travelling to the old mailbox. Run one single update round across all systems in the same week the contact email or phone changes.
Do authority notices sent by email have legal effect?
They carry operational effect: registration supplementation requests, tax notices and reminders, and many other electronic documents are sent through the systems and addresses registered, and response deadlines usually run from successful sending to the registered address — regardless of whether the company has read them. The registered mailbox must therefore be checked daily by a responsible person, and received notices forwarded immediately to the representative and the relevant department.
What if the registered email is lost?
The company faces three risks: missing time-bound authority notices, losing control of electronic accounts authenticated by that email, and difficult recovery because the default authentication channel is the lost email itself. Handling: the legal representative updates new contact information with the business registration and tax authorities using authority-proving papers, recovers or changes the email on each electronic system, and back-checks the loss period for missed notices to remediate before late-response penalties.
Should the representative personal email be used for registration?
It should not. The registered email should be a functional company mailbox (on the company domain or a controlled shared mailbox) with at least two authorised users, because a personal mailbox tied to one individual becomes a choke point when that person resigns, changes number or loses access. Likewise the registered phone should be a stable office or long-term representative number, and every change of the contact person should trigger an information-update round across State systems.
This article has been quality-reviewed by the FLAW AI Legal Council