You can backup IOS by using

iCloud
iTunes
Make a backup using iCloud

Join your device to a Wi-Fi network.
In iOS 8 or later, tap Settings > iCloud > Backup.
In iOS 7 or earlier, tap Settings > iCloud > Storage & Backup.
Make sure that iCloud Backup is turned on.
Tap Back Up Now. Stay connected to your Wi-Fi network until the process completes.

Make sure the backup completed by tapping Settings > iCloud > Storage > Manage Storage, and then select your device. The backup you just made should appear in the information with the time and backup size.

Make a backup using iTunes:

Open iTunes and join your device to your computer.
Save content that you downloaded from the iTunes Store or App Store by clicking File > Devices > Transfer Purchases
Then wait for the transfer to finish. If you're using Windows and you don't see a File menu, hold down the Control and B keys.

If you want to save Health and Activity data from your iOS device or Apple Watch, you’ll need to encrypt your backup: Choose the box called Encrypt [device] backup and make a memorable password.

Write down your password and store it somewhere safe, because there's no way to recover your iTunes backups without this password.
After the procedure ends, you can see if your backup completed successfully in iTunes Preferences > Devices. You should see the name of your device with the date and time that iTunes created the backup.