The expediency of determining the legal and tactical principles of preparation for the appointment of handwriting examinations during the investigation of economic criminal offenses is substantiated. Taking into account the complexity of the mechanism of such crimes, which are often accompanied by the use of forged documents, the significance of special knowledge in the field of handwriting is revealed for solving tasks that go beyond the competence of pre-trial investigation bodies and the court. It was determined that the effectiveness of expert research largely depends on quality preparation: correct formulation of questions, provision of a sufficient number of high-quality comparative handwriting samples and compliance with procedural requirements for their selection. Particular attention is paid to the identification of typical problems in the practice of appointing expertise and analyzing examples from court practice. The value of tactical approaches to the selection of free, conditionally free and experimental samples containing text diversity, repeatability of records and fixing the circumstances of their provision is substantiated. We came to the conclusion that only under the conditions of compliance with the complex approach to the preparation of the examination, it is possible to obtain a reliable opinion of the expert, which will have the appropriate evidentiary value within the framework of criminal proceedings.