Royal Decree R.D. 1829/1999, of 3rd December, approves the Rule governing the lending of postal services, developing what was established by Law 24/1998, of 13th July, regarding the Universal Postal Service and the Liberalization of Postal Services.
Article 31. Admission of requests, documents and communications directed to the organs of Public Administrations.
Requests, documents and communications that citizens or entities direct to the organs of the Public Administrations, through the operator in charge of the universal postal service involved, will be presented in an open envelope, so that the heading of the first sheet of the document to be sent clearly presents the name of the office and the date, the place, the hour and the minute of its admission. These circumstances must also appear on the receipt of its admission. The person sending the documentation, after its comparison with the original document(s), may demand that the above circumstances of the mailing appear on the first page of the copy, photocopy or other type of reproduction of the main document to be sent. This should be presented as a receipt accrediting the presentation of such before the competent administrative agent.
After this procedure, the person sending the documents will close the envelope, and the postal employee will fill out and hand over the receipt of admission, whose original will be filed in the office.
Mailings accepted by the operator in charge of lending universal postal service, following the formalities foreseen in this article, are considered duly presented, to the effects foreseen in article 16 of Law 39/2015, of 1st October, of the Common Administrative Procedure of the Public Administrations, and in the norms for its development.