You should expect to learn how to use spreadsheet software for solving financial problems.
Some business courses in high school can be useful preparation for a career in finance. However, you should take only a few, so that your high school transcript shows that you are preparing for a demanding college-level program. In particular, avoid business math and take academic math courses.
Keep in mind that business is part of the larger culture, so you should take courses in non-business subjects. Good skills in writing, speaking, and critical thinking are needed for advancement in the business world.