Tax avoidance is a major component of underground activities or the irregular part of the economy to reduce taxes, and economists are increasingly looking to analyze this phenomenon. In fact, tax avoidance refers to the efforts of a person, company or institution to reduce taxes paid, and is a kind of use of legal loopholes in tax laws to reduce taxes. Tax avoidance is a tax evasion activity, without breaking the lines of law and within the framework of tax law. Given that the tax structure is highly dependent on the governance structure and improvements in the governance structure and control of corruption lead to public confidence in the government and can reduce the underground economy and tax avoidance, examine the relationship between the quality of institutions and good governance. Tax avoidance is also important. In this approach, we will review tax, tax evasion, tax avoidance and examine the impact of tax avoidance factors on the economy.