When you sync your iPhone, iPad or iPod with iTunes, it creates iTunes backup files on your computer so that you can extract or restore the iTunes backup when you need it, like losing data. However, as time goes on, the old iTunes backup becomes useless and takes up much local disk space on the computer. So if you want to free up some storage space, you can easily delete the old iTunes backup files on your Mac or Windows PC.
Note: When deleting iTunes backups on your computer, please don't connect your iOS device to Mac or Windows PC with USB cord.
Step 1. Launch iTunes on your Mac. On the left top of iTunes window, please click "iTunes" menu, then hit "Preferences..." option.
Step 2. Click "Devices" option, here you will see a list of iTunes backup files from all devices that you have backed up to this computer.
Step 3. Then you might select the backup files you want to delete according to the iTunes backup's device name, date and time. After selection, please click "Delete Backup" option and "OK" to remove iTunes backup from your Mac computer.
Step 1. Launch iTunes on your personal computer, and click "Edit" option on the left top of iTunes window.
Step 2. Hit "Preferences" and then "Devices". Here you can select the desired iTunes backup to delete from a list of iTunes backup of different iOS device.
Step 3. After selection, please click "Delete Backup" option on the bottom and hit "OK" to start deleting iTunes backup on iTunes.
Besides, if you have also synced your iOS device with iCloud, you might also like to know how to delete iCloud backup if needed.