Back Up Your Device to iCloud
It's important to keep your iPhone or iPad backed up to iCloud, especially if you're installing an iOS update or upgrading your phone. Having a recent backup is the fastest way to restore everything, including your settings, when resetting your device or setting up a new purchase.
You can set your iPhone or iPad to automatically back up by going to Settings > iCloud > Backup and toggling on iCloud Backup. Your device will now automatically back up when plugged in, locked, and connected to Wi-Fi. You can also manually back up your device by going to Settings > iCloud > Backup, and selecting Back Up Now. Manage Your Apple ID Account
You can do everything short of actually changing your Apple ID right from your iPhone settings by going to Settings > iCloud and then tapping on your name and entering your password. Here you can update your contact information, change your security questions, and create a new password. Under Contact Information, you can also choose whether or not to receive news and announcements from Apple or change your primary payment method under Payment. If you want to change your Apple ID, you can go online to appleid.apple.com, sign in, and select Edit, then Change Email Address under Account settings.
If you've recently upgraded your iOS device, you've probably noticed that your older device still appears under iCloud's list of backups. These previous backups take up unnecessary storage space and (assuming you have your most recent iPhone backed up) they don't really do you any good.
To delete an old backup, go to Settings > iCloud > Storage. Next, select Manage Storage. Under Backups you'll see a list of all the devices you have backed up to iCloud. Tap on the name of the device you no longer want backed up, and then tap Delete Backup.