iOS is the name of the operating system that is in use in iPhone and iPod Touch. In iPad, a variant of iOS named iPadOS is in use.

This page provides some links that should be useful when you learn to develop applications (apps) for iOS-based devices.

• iOS Developer Center
   
• App Store Connect:    Support    Help    Login
   
• RGB Colors.    Colors    UIColor    Core Graphics
   
• SwiftUI:   View    SwiftUI documentation
   
• UIKit:   UIView    UIViewController    UIKit documentation
   
• Wiki:   iOS    iPadOS    iPhone    iPad    iPod    Xcode    macOS
   
• Swift and UIKit Exercises:   in FINNISH    in ENGLISH
   
• iOS SwiftUI Exercises:   in FINNISH    in ENGLISH
   
• Simple Apps:   SwiftUI    UIKit/Swift    UIKit/Objective-C