Before we install Visual Studio, we need to download and install Xcode. Xcode is the official development IDE from Apple and contains all the tools available for iOS development, including SDKs for iOS, macOS, tvOS, and watchOS.
We can download Xcode from the Apple developer portal (https://developer.apple.com) or from the Apple App Store. I recommend that you download it from the App Store because this guarantees you have the latest stable version. The only reason to download Xcode from the developer portal is if you want to use a prerelease version of Xcode to develop it for a prerelease of iOS.
After the first installation, and after each update of Xcode, it is important that you open it. Xcode often needs to install additional components after an installation or an update. We also need to open Xcode to accept the license agreement with Apple.