Mandatory electronic invoicing!

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Electronic Invoicing became mandatory in Public Administration in 2021

In January 2021, electronic invoicing became mandatory for public procurement, in accordance with the European Directive 2014/55/EU.

According to the recent changes introduced by the Decree-Law No. 14-A/2020 of 7 April, within the scope of the exceptional measures approved in the context of the COVID-19 pandemic, the deadlines established by article 2 of the Decree-Law No. 123/2018 of 28 December were altered, defining its compulsory adoption until the 31st of December 2020 for large companies, until the 30th of June 2021 for small and medium-sized companies and, until 31st of December 2021 for micro-companies.

Electronic Invoicing has new rules

The Decree-Law No. 28/2019 of 15 February regulates several aspects about the issuance of invoices, including electronic invoicing.


An electronic invoice is a document identical to the traditional paper invoice, maintaining an identical legal value, but with an entirely digital life cycle: the issuing, sending, receipt and storage of invoices takes place solely by electronic means. The authenticity of the origin and the integrity of the electronic invoice content must be guaranteed using a Qualified Electronic Seal, in case of legal entities, and a Qualified Electronic Signature, in case of individuals.

Decree-Law No. 28/2019

Change in the type of digital certificate to be used: qualified electronic seal or qualified electronic signature.

Decree-Law No. 123 / 2018

of 28 December, as amended by Decree-Law No. 14-A / 2020

31 DECEMBER 2020

Large companies:

+250 employees

> 50,000,000 turnover

> 43,000,000 balance sheet

30 JUNE 2020

Small and medium-sized companies

31 DECEMBER 2021



Choose a solution suitable to your needs!

HSM Cloud Qualified Certificate for
Electronic Invoicing

Ideal solution for using software already integrated with DigitalSign
Legislation now requires all electronic invoices to be signed with a Qualified Digital Certificate (Qualified Electronic Seal).
See here if your Software is already integrated with DigitalSign.

Certificate valid for 12 Months

DS Invoice

If your invoicing software is not yet integrated with DigitalSign, you can use the DS Invoice application, a low-cost and user-friendly solution, which guarantees full compliance with the applicable legislation, to sign and send your invoices to your customers.

Includes Certificate valid for 12 Months

* To all mounts must be added the VAT at the tax rate in force


The main advantages of acquiring a Qualified Seal for documents and Electronic Invoicing


Guarantees the identity of the entity issuing the electronic invoice.


Allows the detection of any changes made to the electronic invoice’s content.


Guarantees the existence of secure mechanisms on the creation of electronic invoices, which allows its control.


Get to know the recent legal developments applicable to Electronic Invoicing

See here our press release on the subject and consult below the documents issued by the Portuguese Tax Authority and the National Security Office (GNS).

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We prepared some answers for you ...

An invoice is a commercial document whose issuance is generally mandatory for all transmitters of goods, or services providers, being an essential element for the Value Added Tax (VAT), which gives purchasers of goods or recipients of services a credit before the State, which is embodied in the exercise of the right to deduct the tax incorporated therein.

The electronic invoice is the same commercial document, but reduced to an electronic format, that is, ‘dematerialized’. The electronic invoice has the same legal value as the paper invoice, as long as it contains the mandatory information for any invoice and meets the conditions required by law, to guarantee the authenticity of its origin and the integrity of its content.

No. It is already possible to adopt electronic invoicing, containing the applicable legislation to all elements necessary for its rightful adoption.

There are two different types of electronic invoicing: invoices with structured format and unstructured format.

In electronic invoicing, for the private sector, there is no obligation to use a specific format as long as its authenticity and integrity are guaranteed.

Electronic invoices issued by one entity and signed by another legally distinct is not accepted by the Tax Authority, as it does not comply with the applicable law. This way, the aim is to guarantee the principle of authenticity of invoices and the issuer's responsibility, safeguarding that the entity signing the invoices is their author.

In this sense, if you use an electronic invoicing platform, always require that your invoices are signed with a digital certificate issued on behalf of your company.

It depends on the applicable legal requirements. In Spain, for example, the law imposes the obligation to use a qualified certificate to sign electronic invoices.

Thinking about its customers and considering this reality, DigitalSign is preparing the launch of a new product: the qualified digital certificate stored in software for electronic invoicing.

Yes, as long as the certificate has no limitations on the scope of its use. It is also important to bear in mind that if you use a digital electronic seal certificate, intended exclusively for legal persons, you benefit from the fact that no personal data is shared, only the data of the organization.

Taxpayers who electronically issue or receive invoices or equivalent documents must keep them on paper and in lists identifying them, for each tax period (monthly or quarterly), and these lists must contain, in particular, the identification of the invoices (numbers and date), the identification and TIN (tax identification number) of the issuer and receiver, the amount of VAT paid and the total amount of the invoice (art. 45 and art. 48 of CIVA).

Certainly! This type of process depends, above all, on two factors: market adhesion and inter-company business rules. Coexistence between the electronic invoice and the paper invoice is inevitable.

Yes, the Law allows the operation of the computer system or the data storage to take place outside the country. In this case, the taxable person being inspected must provide the Portuguese tax administration access from the national territory and ensure the necessary support, namely through the instruction on the procedures to be adopted to access the invoicing support computer system and to consult the data stored.

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