Application development is the name of the profession that employs people who design, develop and deploy these computer applications.
Application developers have a computer programming background. As you might imagine, the reason it's called application development instead of just computer programming is because there are many more steps involved before and after the actual writing of the computer program. All of those steps are very typical and are collectively called a systems development lifecycle.
The development of specialized programs or sets of specialized programs and associated documentation designed to carry out a particular task.