Office operations in the Republic of Croatia are regulated by the Decree on Office Operations, NN 75/21 in order to achieve a equable way of working of public law bodies in dealing with in writing. With the ingress of the Republic of Croatia to the European Union, regulations with legal acquis of the European Union and define strategies and plans for the development of public administration. In relation to the Decree on office operations, NN 7/09, Decree on office operations, NN 75/21 is conceptually richer and harmonized with existing regulations. The way to be literate introduced into the information system of office operations takes on a completely new form as well as management record. The aim of the adoption of the Regulation on office operations, NN 75/21 is the adoption of the legislative framework in the process of digitization of office operations, with which he wants to relieve himself access of citizens to public law bodies in exercising rights and fulfilling obligations. Digitization of office business is a prerequisite for the implementation of a series of projects that will contribute to the transformation public administration, and thus more efficient communication between public law bodies and parties. The final paper will present new concepts from the Regulation on office operations, NN 75/21 as well as changes in the basic terms of office operations in relation to the regulation that was in force until its adoption. Onwards, the paper will give an overview of the novelties in the Instruction on number markings written and content records of office operations, NN 132/21, which introduced new administrative areas and activities for the purposes of defining classification marks and newspapers in list of numerical codes of public law bodies, which is now in electronic form, and in which they are finally harmonized names of public law bodies in the Republic of Croatia.