Back up your iPod touch, iPhone, or iPad
When you connect your iPod touch, iPhone, or iPad to your computer, certain files and settings on your device are automatically backed up to your computer. You can restore this information to your device if you need to (if you get a new iPhone, for example, and want to transfer your previous settings to it).
Automatically backed-up information includes text messages, notes, call history, contact favorites, sound settings, widget settings, and more. In addition, photos in Camera Roll or Saved Photos are also backed up. Other media files (such as songs, videos, and some photos) aren’t backed up, but can be restored by syncing with iTunes.
If you have iOS 3.0 or later and Mac OS X 10.5.7 or later, iTunes can also encrypt your backups to secure your data.
Back up or restore your device
Connect your iPod touch, iPhone, or iPad to the computer you normally sync with and select your device.
Do one of the following:
Back up or restore from a backup manually: Click Back Up Now or Restore Backup.
Restore your device’s files and settings: Click Restore.
If your backup is encrypted, iTunes asks you to enter the password before restoring your files and settings. Encrypted backups have a lock icon in the list of backups in iTunes Devices preferences.
Encrypt your backups: Select "Encrypt Device backup," type a password, and click Set Password.
Click Back Up Now or Restore Backup (below Backups).
For more information, see the User Guide for your device or the Apple Support website.