Article 9 clarifies the tax treatment of supplies of goods and services facilitated through an agent. It establishes a critical distinction based on the agent's legal capacity. When an agent acts transparently, specifically in the name of and on behalf of a principal, the transaction is legally considered a supply made directly by the principal. Conversely, if an agent provides goods or services while acting in their own name, the supply is treated as a direct transaction by the agent. This distinction is fundamental in determining which party—the principal or the agent—is deemed the supplier for tax purposes.