The document provides an overview of the Common Technical Document (CTD) format, established by the ICH for drug registration submissions in the U.S., EU, and Japan. It outlines the CTD's history, structure, benefits, and the introduction of the electronic version (eCTD) to enhance submission efficiency, accuracy, and communication. The CTD format includes detailed modules covering administrative information, summaries, quality data, non-clinical and clinical study reports, and emphasizes harmonization across international regulatory bodies.