There are numerous definitions of audit, of which a significant number are those related to external audit. Considering that audit can be defined as a process of checking and evaluating financial statements, data and methods used in preparing financial statements in order to present an opinion to interested parties regarding the true and fair presentation of the company's financial statements. There are different types of audits according to the allocation criteria, so there are internal and external audits, business audits and audits of financial statements, commercial and government audits. Audit, depending on the type, provides certain information that is reliable, independent and objective to interested parties, but also serves as a basis or tool for improving corporate governance. It is the greater contribution of audit and the departure from the traditional review of almost exclusively financial information that is the direction in which the audit profession is developing, both internally and externally. Internal and external audit are often viewed as two opposing concepts, but these are two audits that are complementary to each other and between which there is a relationship of cooperation. The quality of the internal auditor's work contributes to relieving the work of the external auditor, who can rely on the procedures performed by the internal auditor during the audit of the financial statements. On the other hand, the results of the external audit also contribute to the internal audit in the form of revealing irregularities or non-compliances that the internal auditor missed.