SwiftUIでさまざまなデバイスのプレビューを確認する方法です。

まず以下のコマンドでデバイスの一覧を確認します。 デバイス名は正確に入力する必要があります。

$ xcrun simctl list devicetypes

== Device Types ==
iPhone 4s (com.apple.CoreSimulator.SimDeviceType.iPhone-4s)
iPhone 5 (com.apple.CoreSimulator.SimDeviceType.iPhone-5)
iPhone 5s (com.apple.CoreSimulator.SimDeviceType.iPhone-5s)
iPhone 6 Plus (com.apple.CoreSimulator.SimDeviceType.iPhone-6-Plus)
iPhone 6 (com.apple.CoreSimulator.SimDeviceType.iPhone-6)
iPhone 6s (com.apple.CoreSimulator.SimDeviceType.iPhone-6s)
iPhone 6s Plus (com.apple.CoreSimulator.SimDeviceType.iPhone-6s-Plus)
iPhone SE (1st generation) (com.apple.CoreSimulator.SimDeviceType.iPhone-SE)
iPhone 7 (com.apple.CoreSimulator.SimDeviceType.iPhone-7)
iPhone 7 Plus (com.apple.CoreSimulator.SimDeviceType.iPhone-7-Plus)
iPhone 8 (com.apple.CoreSimulator.SimDeviceType.iPhone-8)
iPhone 8 Plus (com.apple.CoreSimulator.SimDeviceType.iPhone-8-Plus)
iPhone X (com.apple.CoreSimulator.SimDeviceType.iPhone-X)
iPhone Xs (com.apple.CoreSimulator.SimDeviceType.iPhone-XS)
iPhone Xs Max (com.apple.CoreSimulator.SimDeviceType.iPhone-XS-Max)
iPhone Xʀ (com.apple.CoreSimulator.SimDeviceType.iPhone-XR)
iPhone 11 (com.apple.CoreSimulator.SimDeviceType.iPhone-11)
iPhone 11 Pro (com.apple.CoreSimulator.SimDeviceType.iPhone-11-Pro)
iPhone 11 Pro Max (com.apple.CoreSimulator.SimDeviceType.iPhone-11-Pro-Max)
iPhone SE (2nd generation) (com.apple.CoreSimulator.SimDeviceType.iPhone-SE--2nd-generation-)
iPhone 12 mini (com.apple.CoreSimulator.SimDeviceType.iPhone-12-mini)
iPhone 12 (com.apple.CoreSimulator.SimDeviceType.iPhone-12)
iPhone 12 Pro (com.apple.CoreSimulator.SimDeviceType.iPhone-12-Pro)
iPhone 12 Pro Max (com.apple.CoreSimulator.SimDeviceType.iPhone-12-Pro-Max)
iPhone 13 Pro (com.apple.CoreSimulator.SimDeviceType.iPhone-13-Pro)
iPhone 13 Pro Max (com.apple.CoreSimulator.SimDeviceType.iPhone-13-Pro-Max)
iPhone 13 mini (com.apple.CoreSimulator.SimDeviceType.iPhone-13-mini)
iPhone 13 (com.apple.CoreSimulator.SimDeviceType.iPhone-13)
...

参考: previewDevice(_:)

ContentView.swift

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("swiswiswift.com")
            .font(Font.system(size: 40).bold())
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            ContentView()
                .previewDevice("iPhone 8")
                .previewDisplayName("iPhone 8")
            
            ContentView()
                .previewDevice(PreviewDevice(rawValue: "iPhone 12 mini"))
                .previewDisplayName("iPhone 12 mini")

            ContentView()
                .previewDevice(PreviewDevice(rawValue: "iPhone 13"))
                .previewDisplayName("iPhone 13")
        }
    }
}