Your ClinicalKey account will be the same account used for Embase, ScienceDirect, and Scopus, so if you already have any of these accounts, you will not have to make a new account.
The mobile app allows users to access ClinicalKey remotely and save content for later use. Without an account, you can sign-in with your DUQ authentication and review the available content. However, to make full use of the option to save content and other special features you will need to make your own Elsevier account.