Some colleges (ex the University of CA system) accept by majors and it is hard to change into a more competitive major. Other colleges accept by school (ex. business school, school of liberal arts, engineering school) and it can be hard to change into a more competitive school at the university. A number of schools do not accept by major and they fully understand that students are free to switch majors the minute they set foot on campus.
IMO your friend was probably not accepted to Harvard because he/she expressed interest in studying history (which is not an unusual major) --he/she probably could just have easily written about a passion for biology. I’m guessing there were other attributes that caught the eye of the admissions department.
I’ve heard college admission officers at colleges that don’t accept by major say that they don’t pay much attention to intended major in the admission process since about half of the applicants apply undecided and about 50% of those coming in with a designated major end up switching it while they are at college. There could be an exception if a student has a long standing and demonstrated history of interest/aptitude (perhaps through ECs, research, classes etc.) in some obscure major.
Keep in mind that any ploy you come up with to try to get an edge in admissions, college adcoms have seen thousands of times over. IMO your time would be better spent searching out a group of reach, match, and safety schools based on your academic stats that appear affordable and that you would be happy to attend.