The Wavelet Design & Analysis app is included in Wavelet Toolbox. You can find it, along with the rest of the apps for your installed products, by clicking the Apps tab in the MATLAB Toolstrip.
The Wavelet Design and Analysis app accesses the various graphical tools available in the Wavelet Toolbox.
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.