Password for Software update on iPad

A passcode would be a four or more numerical digits you would enter when you first power-up your iPad. You would had to have enabled this as an additional security feature to access it.

Ref: Use a passcode with your iPhone, iPad, or iPod touch - Apple Support

Hello,

Are you entering your password or passcode? You must enter iPad's passcode whenever you update it system software.

You're very welcome! I'm glad you got it worked out.