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A notification must contain the full text of the decision and state whether it ends the administrative procedure. It must identify the available administrative and judicial remedies, the bodies before which they may be brought, and the time limits (Article 40(2), Law 39/2015).
Tax assessments have additional statutory particulars (Article 102(2), General Tax Law 58/2003): the taxpayer’s identification; the elements determining the amount due; reasons, including the relevant facts and legal grounds, when the assessment departs from the taxpayer’s return or legal treatment; available remedies, competent body and time limit; where, when and how to pay; and whether the assessment is provisional or final. The law does not require every assessment to list a fixed checklist of items such as a tax rate or taxable event regardless of the tax and calculation: it requires the elements that determine the amount, with the applicable explanation and reasons.
The former six-month rule for a notice with the full text but missing other formal particulars is no longer the rule. Under Article 40(3) of Law 39/2015, such a notice takes effect when the interested party acts in a way that shows knowledge of the decision’s content and scope, or files an appropriate appeal. The consequence is not triggered simply after six months, nor does a formal protest by itself establish the statutory effective date.
Official sources: Law 39/2015, Article 40, https://www.boe.es/buscar/act.php?id=BOE-A-2015-10565 ; General Tax Law 58/2003, Article 102, https://www.boe.es/buscar/act.php?id=BOE-A-2003-23186
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