Authorised Courier obligations require valid agency authorisations and authorized electronic declarations to ensure compliant customs clearance processes. Regulation 12 requires an Authorised Courier to obtain agency authorisation from consignors or consignees for customs clearance (with limited post delivery exceptions for low value and specified consignments), file electronic declarations through duly licensed and examined personnel, verify client identity and IEC using reliable documents, exercise due diligence over information submitted, refrain from withholding information from entitled parties or Assessing Officers, avoid influencing customs officers, maintain records for five years, and comply with all relevant customs laws and regulations.