Article 32 provides a legal presumption regarding the timing of notice delivery via post. A notice sent by post is 'deemed' to have been received at the specified address 15 days after the date of sending. This presumption holds unless the taxpayer can provide evidence to the contrary. This rule is critical for calculating deadlines for appeals or responses, as it establishes a fixed starting point for the legal timeline, preventing taxpayers from claiming non-receipt to avoid compliance or delay legal proceedings.