As it is necessary to download an app for one-time password authentication, it is a slightly more difficult operation than setting up "Authentication by email" or "Biometric authentication, Passcode authentication, etc."
If you find it difficult, please set up "Authentication by email."
If you have a device with a screen unlock function, please consider using "Biometric authentication, Passcode authentication, etc."
https://www.expo2025.or.jp/wp/wp-content/themes/expo2025orjp_2022/assets/pdf/tickets-index/id_registration_manual_en.pdf