How to delete iPhone backups from iTunes?
To delete old iPhone backups using iTunes follow these steps:
1. Open iTunes.
2. Navigate to the menu iTunes -> Preferences.
3. Select Devices.
4. From the list of Device Backups, select the backup you wish to delete.
5. Click the Delete Backup button.
Encrypted backups will be marked with a padlock icon. When the backup is deleted the process is complete.