Its using Tab, so only works in iOS 18/Sequoia.
Here's a more complete example:
struct TabTestUIView: View {
var body: some View {
TabView {
Tab {
Text("mail page goes here...")
} label: {
Image(systemName: "envelope")
}
Tab {
Text("setting page goes here...")
} label: {
Image(systemName: "gearshape")
}
}
}
}