Electronic Invoicing in Thailand

Mandatory Use

In Thailand, electronic invoicing is optional. Its use has been allowed since 2012 and may be voluntarily adopted by any VAT-registered business or professional. The government actively promotes it as part of its digitalization policy, highlighting benefits such as efficiency and reduced administrative costs. There are no restrictions by sector or taxpayer type, and e-Receipts can also be issued for B2C transactions. The only requirements are VAT registration and obtaining approval from the RD.

Invoice Format

The technical format of Thai electronic invoices is based on XML, in accordance with the standard defined by the ETDA. The current specification is known as “Standard 3-2560”, published by the ETDA in 2017, which establishes the data structure for e-Tax Invoices and e-Receipts.

Electronic Signature

A key feature of Thailand’s e-Tax system is the mandatory use of electronic signatures on all electronic invoices and receipts. Each e-invoice must be digitally signed by the issuer using a digital certificate recognized by the tax authority. This certificate is typically issued by a Certification Authority (CA) authorized and approved by the RD and uniquely identifies the issuing taxpayer.

Invoice Archiving

Electronic invoices must be archived in their original electronic format for a minimum legal retention period, meeting requirements for integrity and availability. Under the Thai Tax Code and the 2022 regulations, electronic records must be archived for at least five years from the date of the related tax return or the date of issuance of the document.

The law also sets a maximum retention period of seven years, unless an ongoing audit process requires it to be extended.

Invoice Workflow

The operational process for electronic invoicing in Thailand can be described in several consecutive stages:

1. Generation: The issuing taxpayer creates the invoice using their IT system or an approved platform. Before finalizing, the system applies internal validation checks to ensure no required field is missing. Once internally validated, the invoice is digitally signed with the issuer’s certificate.
2. Delivery to the customer: With the invoice signed, the issuer delivers it to the buyer through electronic means.
3. Reporting to the RD: Within the established deadline (by the 15th of the following month), the issuer—or their service provider—transmits the invoice data in XML format to the Revenue Department.
4. Tax validation: The Revenue Department verifies the data received. After verification, the RD sends an electronic response to the issuer (or their service provider).
5. Storage and availability for audit: Finally, both the issuer and the recipient must retain the electronic document.