iCloud and Apps
However, the iCloud Settings panel also includes a number of options that determine how iCloud works with individual apps on your iPhone or iPad. If you want to share your Mail messages, Contacts info and Calendar events across all your devices then you need to make sure that you turn on iCloud for each of these apps here. You can also use iCloud to share information from other apps too, such as Reminders and Notes, bookmarks that you have stored in Safari, and also the Passbook app that stores information about airline tickets and for now is your link to Apple Pay.
It's worth being selective here, as not all apps really need to share data and info across your devices. I have lots of web pages bookmarked on the iMac in my office, but I don't want to mix them up with other web pages that I view on my iPhone, so I tend to turn off iCloud sharing for Safari most of the time.
iCloud and Apps: Mail options
Although there's a simple switch that allows you to turn iCloud On or Off for Mail there's also another set of Mail options that are hidden further down in the iCloud Settings panel. Scroll right down to the 'Advanced' section and tap on the entry for Mail. That opens up a page that contains options for managing multiple email accounts. Scroll down again, and tap on 'Advanced' again, and you'll now see a window that allows you to control how Mail handles different mailboxes. You can actually change which mailboxes are used to store emails that you send and receive. If you're an email obsessive - or Hillary Clinton - you could specify that emails that you discard are archived for future retrieval, rather than going straight into the Trash and being deleted.
You can also specify how long deleted messages stay in the Trash before they are completely removed. You can keep them for one day, one week or one month, or select the 'Never' option which leaves messages in the Trash until you decide to delete them yourself.
iCloud and Apps: iCloud Backup
Important apps like Mail and Safari get their own individual controls for iCloud, but there's another option in here, simply called Backup, that allows you to store data from a number of additional apps too.
The Backup option is a little confusing, as it overlaps with the iCloud Photo Library to some extent. Turning on iCloud Photo Library stores your entire Photo Library in iCloud and updates it continuously whenever you shoot any new photos and videos. The Backup option works slightly differently - in fact, it's a bit more like doing a Time Machine back-up on your Mac.
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