iTunes and iCloud backups each contain a lot of data, and they're broadly similar.
If you are using iTunes backups and your backup is not encrypted, it won't contain Health data or saved passwords (ie. your Apple Keychain). If you are using an encrypted iTunes backup, it will be broadly similar to an iCloud backup in terms of its content.
Data contained in an iTunes or iCloud backup
- Data from built-in Apple apps: Notes, Calendar, Messages (iMessages, SMS, MMS), Call history, Safari browser history, Photos, Videos
- Data from third-party apps which store it in the backup. In practise, this is most of them. WhatsApp, Kik, Hike, Viber, WeChat, etc. all store rich data in backups.
- Device and network settings
- Keychain and password data
- Lots of forensic data
Note that it is possible to manually configure your backups so as not to include some of this data.
Data not included in an iTunes or iCloud backup
- Email messages from the default Apple Mail app
- Your iTunes Music and Videos.
- The app installation (