Dear Arshad,
Year of Passing means the year in which gave your final exam and completed your class. Hence, you should fill the entry in you improvement exam form accordingly.
If you had given the final exams last year and completed 10th class in 2019, then you should fill 2020 in the Year of Passing entry of your improvement exam form.
Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile