My iPhone asks for codes to unlock adult sites that are being blocked access to open

You have Restrictions activated in Screen Time. What your iPhone is doing is asking you to enter the Screen Time passcode to disable sites that are not allowed.

You will need to ask the person that setup Screen Time Restrictions on your iPhone to allow you to access adult sites. If you are the Screen Time administrator then you can do the following (You will need to input the Screen Time Passcode):

Open Settings ➔ Screen Time ➔ Content & Privacy Restrictions ➔ Content Restrictions ➔ Web Content : Set this to Unrestricted Access.

Axel F.

Go to Settings/Screen Time/Content & Privacy Restrictions/Content Restrictions/Web Content and change the setting.