The United States Copyright Office is modernizing its registration practices to increase the efficiency of the registration process for both the Office and copyright owners. To further these efforts, this final rule adopts modifications to the Office's procedures for supplementary registration. Specifically, the Office adopts a new rule that, in most cases, requires applicants to submit an online application in order to correct or amplify the information set forth in a basic registration. In addition, the Office is amending the regulation to codify and update certain practices that are set forth in the Compendium of U.S. Copyright Office Practices, Third Edition and to improve the readability of the regulation.