The iCloud ecosystem is complicated and it's hard to know how much of your data in the "cloud" is secure and synchronized with your devices. We'll go through the set up process and explain what each feature does.
How to Sign in to iCloud
When you set up your Mac for the first time, you should sign in with an iCloud account. If you've already set that up, you can get started right away, but if you're not signed in, you'll need to sign in through the iCloud settings.
Open the System Settings app. Click Apple menu at the top of the screen and select "System Preferences" ̵
These are the iCloud settings. If you are not logged in, you will see this login screen.
If you already have an Apple ID from an iPhone or iPad, make sure you use the same one for your Mac, or nothing will be synced between your devices. However, if you need to create a new account, you can click "Create Apple ID" below to sign in.
You can use your own email address, such as a Gmail account, or create a new email address from @ icloud.com. In both cases, a new iCloud account will be created that you can use on any device you want.
The primary function of iCloud is to sync your important personal information to your devices (and be backed up in the cloud). Most iCloud features instantly sync the following data across all connected devices:
- Your contacts
- Calendar events and reminders
- Safari Data, including passwords, open pages, and browser history
- HomeKit Access  Notes, that you created in the Notes app
- emails you sent and received, and drafts
You should not worry about them as long as you are logged in and will use the option in the iCloud Settings of your Mac. Make sure that the options are also turned on in the iCloud settings on your iOS devices and any other devices that you have registered with the same iCloud account, or that you might experience problems.
<img class = "alignnone wp-image-408208 size-full" data-pagespeed-lazy-src = "https://www.howtogeek.com/wp-content/uploads/2019/03 /ximg_5c918d58d7cf4.jpg.pagespeed.gp+jp+jw+pj+ws+js+rj+rp+rw+ri+cp+md.ic.WLeTzvMqEN.jpg "alt =" iCloud Photos  Photos are closed Note that there are two methods to back up the first iCloud Photos, all captured photos are simply stored in iCloud and synced across multiple devices, and if the device becomes corrupt, you can use iCloud Photos on a new device Enable and re-download all your images in iCloud.
"My Photo Stream" is different and only saves the latest photos for a month to give to your other device Sync device time, that is, when you take a photo on your iPhone If you do not use your iPad for a while, your photos will not sync to your iPad he backed up nothing photos. If you lose your device without "iCloud Photos" enabled, you will not be able to get your pictures back.
There is still a use for "My Photo Stream" because saving every photo you take in iCloud fills the 5GB of free space on iCloud very quickly. If you use two devices that you regularly use, such as a MacBook and an iPhone, activating My Photo Stream can save a lot of space while still backing up your photos to the MacBook. Do not break both at the same time.
iMessage is not enabled by default, but you only need to log in when you start the app for the first time. Just make sure you sign in with the same account you use on your iPhone or iPad, and make sure iMessage is turned on on all your devices.
However, this does not synchronize old messages that you may have on your Mac. To do this you need to enable "Messages in iCloud". After logging in, click on "Messages" in the top menu bar and open the preferences.
 At the top, open the blue "iMessage" tab and make sure "Enable messages in iCloud" is checked.
When this option is enabled, your messages should be synchronized regardless of the time they were sent. You must ensure again that the option is turned on for all devices to work properly.
iCloud Drive is used for everything else. TextEdit documents, your books, your system settings, automator scripts, the entire kitchen sink. If this is a document that you created in a native Apple app, it will probably be synced here.
By default, iCloud Drive also stores the folders "Desktop" and "Documents", which can be very large. You can quickly populate your iCloud account if you keep it up. And if you do not pay Apple $ 0.99 a month for the 50GB iCloud plan, you'll be notified every few hours with notifications prompting you to buy more storage space.
 However, you can not simply disable the Desktop and Documents Folders option to turn off iCloud Drive, as the deactivation process is much more difficult than it should be. You can read our disabling iCloud Drive manual without accidentally deleting your data.
While iCloud Drive takes up a lot of space in iCloud, it's a useful feature if you're choosing more storage space. It saves all your desktop and document folders in iCloud and then removes old files that you do not use from your MacBook to save space. If you need the file again, you can download it from iCloud. So if you have an old MacBook with a small hard drive, you can pay a few bucks a month to get more room to breathe.