Nowadays, papers are taken, stored, and shared more frequently in digital format. At the same time, document image altering software also gets more and more powerful as there is an increasing concern about the authenticity of documents. Texts on real estate agreements, for instance, can be changed to make an illegal deal, and the date on a plane ticket can be changed to get past security and into airport terminals. This study provides an overview of various image processing methods to spot document forging in order to stop such illegal actions. As digital image processing gains popularity in scientific and technical applications and forgery techniques develop quickly, the aim of forgery detection is to maximize the extraction of information from altered photos, particularly noisy and post-processed images. In order to create a new strategy for a future forensic science investigation, the major focus is on various sorts of forgery detection in digital image processing with the aid of all transform approaches and comparing their best results for further improvement.