Article 14 of Law 39/2015 establishes the right and obligation to carry out electronic procedures with Public Administrations, in order to perform any process for administrative procedures on a wide range of subjects. In summary, this is compulsory for all parties except for individuals, as long as they are acting as individual citizens and no other express obligation exists (article 14.3).
In the case of notifications from a Public Administration sent to a party that is obligated to use electronic means of communication, article 41 establishes that these notifications must take place by digital means.
The present form must be used to notify the CNMC regarding the information needed so that electronic notification can be performed. This information essentially consists of a Tax ID Number (NIF in Spanish), with respect to which a recognised electronic certificate is possessed.