Gradient development in iOS involves using the Core Graphics framework or the SwiftUI UI toolkit. Gradients can be created using the CGBitmapContext class for bitmap-based gradients or the CGGradient class for more complex gradients. SwiftUI supports gradients through the LinearGradient, AngularGradient, and RadialGradient structs. Gradients are widely used in UI design to create visually appealing backgrounds and transitions.