DIAN is responsible for helping to ensure the fiscal security of the Colombian State and the protection of national economic public order, by administering and controlling the proper fulfilment of tax, customs, exchange rate, operating rights and administrative expenses on games of luck and chance exploited by public entities at the national level and facilitating operations of foreign trade, and transparency. This report describes the process of professional practice as a student of Public Accounts in the Directorate of National Taxes and Customs SectionalBarrancabermeja, in the Office and in the Division of Collection and Collection Management. Where the taxpayer fails to pay national taxes, the Office (Legal Office) proceeds to implement Article 402 of the Penal Code (Omission of the withholding agent and/or collector), on the other hand, in the Collection and Collection Management Division in the area of Refunds proceeds or in favour of payments due to the refunds/Payments. The internship was conducted in accordance with the functions of the organization and the schedule of these functions to evaluate the knowledge obtained by the student of Public Accounts of the Cooperative University of Colombia, which conformed to the rules that are managed within the public entity Directorate of Taxes and National Customs (DIAN).