MATLAB Compiler Apps enable you to package MATLAB programs as standalone applications, Hadoop libraries, and Excel add-ins. You can find them, along with the rest of the apps for your installed products, by clicking the Apps tab in the MATLAB Toolstrip.
Apps are interactive MATLAB programs you can use without writing any code. Most toolboxes come with apps, and you can download more for free from the MATLAB File Exchange. You can also package and share your own apps.