BACKUP ENCRYPTION
HOW CAN I REMOVE MY BACKUP ENCRYPTION PASSWORD?
CAN I JUST SAY THAT I HAVE NEVER SIGNED UP FOR A BACKUP ENCRYPTION AND IT IS THE MOST ******** THING THAT HAS HAPPENED IN MY LIFE. I AM VERY VERY UPSET.
iPhone X, iOS 12
You don't remove it.
If you encrypted your backup and now can't remember the password, the backup is gone and can't be used.
When you turned on encryption you were warned about this.
About encrypted backups on your iPhone, iPad, or iPod touch - Apple Support
