Proper officer designation under CGST Act assigns specific officer ranks responsibility for registration and composition levy functions. Assignment of functions designates specific Central Tax offices as the proper officers for registration and composition levy under the Central Goods and Services Tax Act, 2017. The Board assigns Assistant and Deputy Commissioners and Assistant or Deputy Directors one set of specified subsections and rules, and Superintendents a distinct set of subsections, sections and rules, thereby clarifying which officer-holders must execute the enumerated registration and composition-related functions under the Act and rules.