Article 14 establishes that a tax return serves as a self-assessment and a commitment to pay. The General Tax Authority reserves the right to amend this assessment based on provided data or perform an estimated assessment if a taxpayer fails to file a return or provide documentation. Taxpayers must be formally notified of any assessment changes via registered mail. Furthermore, liquidators are legally treated as taxpayers for the purpose of assessment procedures during the winding up of an entity. This framework ensures that the Authority can intervene whenever self-reported data is insufficient or absent.