Mobile apps in the context of "Smartwatch"

iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple for its iPhone line of smartphones. It was unveiled in January 2007 alongside the first-generation iPhone, and was released in June 2007. Major versions of iOS are released annually; the current stable version, iOS 26, was released to the public on September 15, 2025.

Besides powering iPhone, iOS is the basis for three other operating systems made by Apple: iPadOS, tvOS, and watchOS. iOS formerly also powered iPads until iPadOS was introduced in 2019 and the iPod Touch line of devices until its discontinuation. iOS is the world's second most widely installed mobile operating system, after Android. As of December 2023, Apple's App Store contains more than 3.8 million iOS mobile apps.

A contact list is a collection of screen names. It is a commonplace feature of instant messaging, Email clients, online games and mobile phones. It has various trademarked and proprietary names in different contexts.

Contacts lists' windows show screen names that represent actual other people. To communicate with someone on the list, the user can select a name and act upon it, for example open a new E-mail editing session, instant message, or telephone call. In some programs, if your contact list shows someone, their list will show yours. Contact lists for mobile operating systems are often shared among several mobile apps.

iTunes is a media player, media library, and mobile device management (MDM) utility developed by Apple. It is used to purchase, play, download and organize digital multimedia on personal computers running the Windows (and formerly macOS) operating systems, and can be used to rip songs from CDs as well as to play content from dynamic playlists. It includes options for sound optimization and wireless sharing.

iTunes was announced by Apple CEO Steve Jobs on January 9, 2001. Its original and main focus was music, with a library offering organization and storage of Mac users' music collections. With the 2003 addition of the iTunes Store for purchasing and downloading digital music, and a Windows version of the program, it became an ubiquitous tool for managing music and configuring other features on Apple's line of iPod media players, which extended to the iPhone and iPad upon their introduction. From 2005 on, Apple expanded its core music features with support for digital video, podcasts, e-books, and mobile apps purchased from the iOS App Store. The release of iOS 5 in 2011 made these devices less dependent on iTunes, though it could still be used to back up their contents.