Hi there, Saransh,
Thanks for visiting the Apple Support Communities. I see from your post that you're trying to set up your MacBook Pro after installing macOS Catalina, and am understanding you'd like to know if it is normal to prompt for your iPad passcode. I'm happy to help!
What you describes sounds to me like iCloud Keychain. With this feature enabled, login credentials for various apps and websites can be shared across your devices. When you first set it up on a device (or set it up after restoring), you're asked for the passcode of a trusted device to verify you and authorize iCloud Keychain.
More information on iCloud Keychain can be found here: Set up iCloud Keychain - Apple Support.
Have a great day.