Reference

The day-to-day operations of approved schools are generally managed by school principals. Principals are responsible for overseeing all school operations, including daily activities, implementing educational policies, ensuring the safety and security of students, and acting as advocates for the school.

For example, according to the Bureau of Labor Statistics, "Elementary, middle, and high school principals oversee all school operations, including daily school activities" (source). Additionally, the role of a principal, as outlined on Grand Canyon University's blog, includes handling the overall operations at the school level (source).

In summary, it is the principal who generally manages the day-to-day operations of approved schools.