What is Samsung Knox?
Samsung Knox is a special security layer found in top-tier Samsung phones that can separate and isolate personal and business user data. For most of us, Knox will be used for Samsung Pass and Secure Folder both of which can be accessed in the Biometrics and security section in your phone's settings.
Samsung Pass stores sign-in information securely and allows you to access it using your phone's biometrics. Secure Folder is a bit more complex in that it creates a new environment for files and apps on your phone. Once you set it up and open the folder you will have a fresh version of these apps that cannot be accessed by the rest of your phone.
By default, once you enter the Secure Folder you only have access to a few apps — Camera, Gallery, My Files, Contacts, Calendar, Samsung Internet Browser, and Samsung Notes. You can add other apps to the Knox-protected layer and they will be "copied" to a place where they and their data is kept separate from the same app on the "regular" layer in your phone.