If you wish to set up "Biometric and Passcode Authentication, etc.", you may need to set up biometric authentication on your phone itself first, depending on the model of iPhone you have.
Please refer to sections "2.2-A Using Biometric Authentication and Passcode <iPhone>" and "2.3 Setting Up a Supported Browser" in the ExpoID Registration Manual below.
ExpoID Registration Manual:
https://www.expo2025.or.jp/wp/wp-content/themes/expo2025orjp_2022/assets/pdf/tickets-index/id_registration_manual_en.pdf

If you are unable to confirm your identity using biometric authentication or passcode authentication, you may be able to confirm your identity successfully by resetting your identity verification method settings.
To reset the identity verification method, please refer to "2.2 Resetting the identity verification method" in the ExpoID Problem Solving Manual below.
ExpoID Problem Solving Manual:
https://www.expo2025.or.jp/wp/wp-content/themes/expo2025orjp_2022/assets/pdf/tickets-index/id_problem_solving_manual_en.pdf

You may also be able to successfully confirm your identity by setting up a method other than "Biometric and Passcode Authentication, etc." such as "Authentication by Email."
Please refer to section "2.2-C Using Email for Authentication" in the ExpoID Registration Manual.
ExpoID Registration Manual:
https://www.expo2025.or.jp/wp/wp-content/themes/expo2025orjp_2022/assets/pdf/tickets-index/id_registration_manual_en.pdf