iOS application development is the process of making mobile applications for Apple hardware, including iPhone, iPad and iPod Touch. The software is written in the Swift programming language or Objective-C and then deployed to the App Store for users to download.
Every app in the app store has to be written in a language called Swift UI. If you are new to programming I would not recommend starting with this course since it has a few prerequisites.
The Course, provided entirely free of cost by Stanford, is 15 videos long and teaches you how to make a simple memory game.