Here you can find complete guide How To Backup iPhone To iCloud on iOS 12, iOS 11, iOS 10.
In this step-by-step instruction, I will talk in detail about how to backup iPhone in iCloud, where backup copies are stored, how to restore the phone from it, how to delete an unnecessary backup and some additional information that may be useful. Ways are also suitable for the iPad.
The iPhone backup contains almost all of your phone data, except for Apple Pay and Touch ID, data that is already synchronized with iCloud (photos, messages, contacts, notes), installed applications.
Step 1. Go to Settings and tapping on your name at the top of the screen.
Step 2: Then, tap iCloud.
Step 3. Scroll down and tap on iCloud Backup. Make sure the switch next to iCloud Backup is turned on.
Step 4. Finally, tap Back Up Now.
You can use this backup after resetting to factory defaults or on a new iPhone: during the initial setup, instead of “Set up as a new iPhone”, select “Restore from iCloud copy”, enter your Apple ID data and perform a restore.