Hi Piyush!

No, it is not mandatory to complete 12th from Himachal Board for HPTET 2021. The eligibility criteria says that :

• candidate must have atleast 50% in senior secondary level and a diploma degree  in Elementary Education
• The candidates who possess 45% in graduation and have  passed or appearing in 1-year Bachelor in Education (B.Ed) are also eligible.

To know more, visit here:

HP TET 2021 Dates, Notification, Registration, Eligibility, Pattern, Syllabus, Answer Key and Result (careers360.com)

Thankyou!