Administrative agencies serve two major functions: rule-making and adjudication (or enforcement). The rules and regulations of administrative agencies and executive documents are generally published in a register and compiled in a code. For example, federal materials are published in the Federal Register (F.R.) and the Code of Federal Regulations (C.F.R.). The State of Michigan publishes the Michigan Register and the Administrative Code of Michigan. Decisions rendered by an agency's adjudicatory body may be published as well. If a decision or order is not published, anyone wanting a copy must contact the agency to receive it.

As in searching for laws, the general subject of a regulation can be searched in the general index that a code provides. To find a rule or regulation in a register, the researcher should know the date of the final regulation or the year of enactment. Most registers have no general index that covers all regulations currently in force.