To best answer your question we would need to know which PowerSchool product you are referring.
The majority of their products are meant to work together and to be purchased by a school or district for widespread deployment. One of their primary products is PowerSchool SIS.
PowerSchool SIS is not meant to be used by a single teacher, but is a school/district product. If your school has already purchased PowerSchool, then there are system administrators within your school with the ability to create accounts. If your school has not purchased PowerSchool and already set it up in a self-hosted or other hosted environment you will not be able to access it as a teacher.
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