P/w transfer from iPhone to iPad

Are you trying to synchronise your saved Passwords (saved in your Keychain - and accessed from iPad Settings) between devices - or something else?

Your iPad and iPhone Passcode are entirely independent of each other - and whilst can be manually set to be the same, are not synchronised in any way. Your AppleID Password is common to all your devices - and your iCloud account that is used to synchronise data between your Apple devices.

If you are trying to synchronise your saved Passwords via iCloud, ensure that your devices are signed-in to iCloud with the same AppleID - and enable Keychain in iCloud:

Settings > [Your Name / AppleID] > iCloud > Keychain > iCloud Keychain - set to ON

What do you mean by this?

You can always change the passcode of your iPad: Use a passcode with your iPhone, iPad, or iPod touch - Apple Support

-- Jay (they/them)