No, you cannot appear for the Class 12 UP Board exam in the English language without filling English as a subject on your registration form; it is mandatory to select the subjects you wish to appear for during registration, and English must be listed if you want to take the exam in English.

To appear for any subject in the UP Board exam, including English, you must select it and fill in the details during the registration process.

You cannot choose to write an exam in English on the day of the exam if you haven't registered for it.

Good luck,!!