The EU and the Member States have been forced in recent years to take a stronger position against the growing trend of tax fraud, tax evasion, and tax avoidance. The EU legislative and non-legislative acts in this area have resulted from political attitudes, economic intentions, proposals, and compromises reached between the individual Member States, on the one hand, and the EU, on the other, in their effort to combat fraudulent behaviour in the taxation area. The fight against fraudulent behaviour in the taxation area, be it tax fraud, tax evasion or tax avoidance, has become a real global challenge not only for the EU and its Member States but also for the entire world. These are different forms and methods for misusing tax systems both within the EU and abroad. This paper is part of the project: “Electronic methods for detecting unusual business transactions in the business environment” (ITMS code: 313022W057), co-financed by the European Regional Development Fund (ERDF) and also the project “VEGA1 / 0194/19 — Research on process-oriented financial management with a focus on to detect tax evasion in international trade”.