What should I do to become a high school history teacher after completing BA in history (graduation)?

Hello Anisha, If you want to make career in the lectureship or Teaching. You could make a very good career by preparing for the Teaching Recruitment Exams conducted by the government. Every year. Some of the important exams are UGC NET and SET. National Eligibility test or UGC NET https://medium.com

You can opt to pursue B.Ed course after graduation.