iPhone Passcode

Sorry, we are confused. Are you asking about a Software Update for the iPhone.......likely to iOS 15.5?

You would not be asked for a passcode if you have not set one up previously.

If you are being asked to enter a passcode, then you must have set up a passcode previously and you will need to enter the passcode to continue. You won't be able to bypass the passcode screen.

Your next question might be......"What if I have forgotten the passcode". If that is the case.......

If you forgot your iPhone passcode - Apple Support

The steps given in this link will help you reset the passcode -> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

If the phone is working without a passcode........then you did not set one up.

Would you like to set one up?

No, and that means that you DID create a passcode when setting up the phone. If you have forgotten it you must restore the phone to its “new phone” state and lose any content you haven’t backed up.