Before updating your phone's software, it's recommended that you back up the phone memory to ensure that no data is lost. It can also be useful to back up the phone memory regularly to ensure that no data is lost in case of defects and crashes. Follow these instructions to back up the phone memory.
Just so you know...
Please select the red text to see instructional images.
Back up the phone memory using iTunes, go to 1a.
Back up the phone memory using iCloud, go to 1b
1a - Back up the phone memory using iTunes
Go to www.itunes.com on your computer.
Find the download section on the web page to download iTunes.
Download and install iTunes on your computer.
Start the program iTunes on your computer.
Connect the data cable to the socket at the bottom of your phone and to your computer's USB port.
Depending on your settings in iTunes, backup may start automatically.
To start backup manually:
Select Back up to iCloud or Back up to this computer.
Right-click your phone in the menu to the left.
Select Back Up.
1b - Back up the phone memory using iCloud
Log on to iCloud if you're asked to do so.
Press Storage & Backup.
Press the indicator next to iCloud Backup to turn on the function.
Press Back Up Now.
To synchronise the contents of your phone continuously, press the indicator next to the required data type to turn on synchronisation. Before you can back up the phone memory using iCloud, you need an Apple ID. If you don't have an Apple ID, you can create one at www.apple.com