What is "xcode"

The Xcode is an integrated development environment and free software from Apple Inc. for project management created for iPhone, iPad, Mac, Apple Watch, and Apple TV.

It has tools for the user to create and improve their applications, accompanied by tools needed to develop applications for Mac OS X, and supports, by default, Objective-C programming languages, Swift and Apple-Script.

Xcode has a set of "extras" for development, these "extras" are called SDK, and are provided by Apple Inc. on iOS development website. Independent companies and developers duly registered in Apple’s iOS developer program, called Apple Developer Program, can distribute applications on App Store.

Official website: https://developer.apple.com/xcode/