Apple's free iCloud service stores subscribers' photos, videos, documents, apps and more and updates everything across users' synced devices.
Replacing Apple's MobileMe storage service in 2011, iCloud enables subscribers to save their address book, calendar, notes, Safari browser bookmarks and photos on Apple's servers. Changes and additions to one Apple device can be pushed to the user's other registered Apple devices.
What does iCloud do?
The iCloud subscription service starts as soon as users set it up by signing in to iCloud with their Apple ID, which they only have to do once on all their devices or computers. After that, any changes made on one device are synced with all other devices that use that Apple ID.
How to set up iCloud
Users must first set up iCloud on an iOS or macOS device; then they can access their accounts on other iOS or macOS devices, the Apple Watch or Apple TV.
On macOS, users can go to the Apple menu, select System Preferences, click iCloud, enter their Apple ID and password, and turn on which features they would like to use.
On iOS, users can tap Settings and their name, then they can go to iCloud and enter the Apple ID and password, and then select features.
After completing the initial setup, users can sign in with their Apple IDs on any other iOS device or macOS computer.
On a Windows computer, users must first download and install iCloud for Windows, then enter the Apple ID and password, select features, and click Apply. Microsoft Outlook syncs with iCloud Mail, Contacts, Calendar and Reminders. Other apps are available on iCloud.com.
The service, which requires an Apple ID, is available on Macs running OS X 10.7 Lion and iOS devices running version 5.0. Some features, such as photo sharing, have their own minimum system requirements.
PCs must have Windows 7 or later to synchronize with the iCloud. PC users must also have an Apple device to set up iCloud for Windows.
An iCloud account includes a free @icloud.com email address -- formerly @me.com. This feature is optional, but users can choose to use the free email address as their iCloud Apple ID.
Find My iPhone
The Find My iPhone feature enables users to geolocate, lock and remote wipe their iPhone, Mac or iPad if it is lost or stolen. This feature was first available to paying MobileMe users in 2009 as part of the iOS 3 software update. It was available for free with the iOS 4.2.1 software update the following year.
An additional feature, called Lost Mode, appeared with iOS 6, enabling users to mark their missing iPhones as lost.
iCloud Photo Stream
The Photo Stream service automatically uploads and store photos in a device's camera roll for access from another device. Any time a user takes a photo or video, it gets pushed to all of their registered devices.
It also lets users store their most recent 1,000 photos for free for 30 days; when the time is up, the files are automatically removed from other devices. The service also integrates with Apple TV.
iCloud Photo Library
The Photo Library automatically uploads any photo or video the user takes to the iCloud. Users can access their files from an iPhone, iPad, iPod Touch, Apple TV, Mac or PC, or on iCloud.com. This feature is available on iOS 8.1 or later and requires an internet connection.
Backup and restore
Users can automatically back up their iPhones and iPads to the iCloud mobile service daily when the screen is locked and the device is connected to Wi-Fi and a power source. Users can also back their data up manually and restore data from an iCloud backup.
Users can save downloads -- including purchases from the iTunes store, the iBooks store and the App Store -- in a digital locker and enable automatic synchronization on other devices, or they can do so manually.
Purchases from the App Store can store settings and data in iCloud so users don't have to re-enter information on multiple devices.
The file hosting service lets users store all of their files in iCloud and access them from any iOS device, Mac or PC.
On a Mac, users can opt to have any files they saved in their Documents folder automatically saved to iCloud Drive. On an iOS device, files will appear automatically in the built-in iCloud Drive app.
Users get 5 GB of storage for free. The iCloud service also offers paid storage plans. Customers can purchase 50 GB of storage for $0.99 per month. 200 GB of storage costs $2.99 per month and 2 TB of storage costs $9.99 per month.