Article 6 of this Decree-Law provides the foundational legal definition for a 'Supply of Services' for tax purposes. The article establishes a broad, residual definition, stipulating that a supply of services encompasses any transaction that is not legally classified as a 'Supply of Goods'. This catch-all approach ensures comprehensive coverage for all non-goods transactions. Furthermore, the provision explicitly states that the definition is inclusive of any specific services that are further detailed and enumerated within the Executive Regulation of the Decree-Law. This empowers the Executive Regulation to provide additional clarity and specify particular transactions that fall under this category.