How to Reset iTunes Encrypted Backup Password?

If you can’t remember the password for your iPhone encrypted backup, please try to reset it.
If you have a device with iOS 11 or later, you can make a new encrypted backup of your device by resetting the password.
On your device, go to Settings > General > Transfer or Reset [Device], then tap Reset.
Tap Reset All Settings and enter your device passcode.
Tap Reset All Settings.
Follow the steps to reset your settings. This won't affect your user data or passwords, but it will reset settings like display brightness, Home Screen layout, and wallpaper. It also removes your encrypted backup password.
Connect your device to the Finder, the Apple Devices app, or iTunes again and create a new encrypted backup.
You won't be able to use previous encrypted backups, but you can use the Finder, the Apple Devices app, or iTunes to back up your current data and set a new backup password.

If you have a device with iOS 10 or earlier, you can't reset the password.
In this case, try the following:
If someone else set up your device, ask them for the password.
Use an iCloud backup instead. If you don't have an iCloud backup, you can make one.
Use an older Apple Devices app, iTunes, or Finder backup.