A segment is a view of your application that determines the layout, theme, localization, date and time, and time zone settings of all the DataPages for a single user role. You can use segments to make your application look different for every user role that you define.  

An application can have two types of segments. Every user role that you configure has its own protected segment that only users within that role can access after logging in to the application. When you create a role, App Designer automatically adds a dedicated segment that is the only segment for that role. Additionally, every application has a special Public access segment that does not require user authentication at all, which means that everyone, whether logged in or not, can access the DataPages in this segment. 

A fragment of the App Designer left panel showing DataPages grouped in two segments.

You can control the following behavior on all DataPages within every segment: 

 

To ensure that every page and every object on any page shows the same, consistent style and comparable experience, you can choose themes and modify templates for your segments: