iCloud automatically backs up all of the data on your iPhone or iPad every day, so long as the device is connected to Wi-Fi, turned on, locked, and connected to a power source. This makes it easy to restore a device if you need to wipe it or set up a brand new iPhone or iPad with your existing data.
Here’s what gets backed up to iCloud:
iTunes purchase history
Photos and videos (unless you have iCloud Photo Library enabled)
Home screen and app ogranization
iMessage, text messages, MMS messages (if restoring, the SIM card used during back up is required)
Visual Voicemail password (if restoring, the SIM card used during back up is required)
It can end up being quite a lot of data, which can take up a good chunk of your iCloud storage.
Why it’s good to keep your iCloud backups
Holding onto your iCloud backups means you get to take your data virtually anywhere, with the ability to access and restore your iPhone or iPad’s data from just about anywhere. It’s particularly handy for folks with multiple devices, especially those who rely on Accessibility settings, since you don’t have to manually set everything up again.