Generally, users who visit web applications don't have any clue about the functionality, accuracy, or quality of the code of the application. Instead, they decide the value of the application based on its user interfaces and the simplicity of using its features. Most expert-level web developers tend to give more focus on development tasks in complex applications. However, the application's design plays a vital role in building the initial user base. WordPress uses themes that allow you to create the frontend of web applications with highly extendable features that go beyond conventional layout designs. Developers and designers should have the capability to turn default WordPress themes into amazing frontends for web applications.

In this chapter, we will focus on the extendable capabilities of themes while exploring the roles of the main theme files for web applications. Widgetized layouts are essential for building flexible applications, and...