iOS app development involves creating applications for Apple’s iOS operating system, primarily used on iPhones and iPads. Developers typically use Swift or Objective-C programming languages alongside the Xcode integrated development environment (IDE), which provides tools for designing, coding, testing, and debugging. Key elements include understanding Apple’s Human Interface Guidelines for user experience, utilizing frameworks like UIKit and SwiftUI for UI design, and integrating APIs for functionality. The development process includes stages like planning, coding, testing, and deployment, ultimately publishing apps on the App Store, where they can reach millions of users.