Use school when referring specifically to a K–12 educational institution. In other cases — for example, educational institutions providing post-secondary/higher education, trade, or career education or institutions that are not unambiguously schools — use institution.
This rule exists in part because it is incorrect to confuse the terms college and university. Not all post-secondary academic institutions are universities, and many universities are organized into subdivisions called colleges.
K–12 only
Higher education or combined audience
You cannot create student accounts for a different college.
You cannot create student accounts for a different academy.
You cannot create student accounts for a different school.