To develop iOS apps using the latest technologies , you need a Mac computer (OS X 10.10 or later) running the latest version of Xcode. Xcode includes all the features you need to design, develop, and debug an app. Xcode also contains the iOS SDK, which extends Xcode to include the tools, compilers, and frameworks you need specifically for iOS development.
Download the latest version of Xcode on your Mac free from the App Store.
To download the latest version of Xcode
Open the App Store app on your Mac (by default it’s in the Dock).
In the search field in the top-right corner, type Xcode and press the Return key.
The Xcode app shows up as the first search result.
Click Get and then click Install App.
Enter your Apple ID and password when prompted.
Xcode is downloaded into your /Applications directory.