The Federation of State Boards of Physical Therapy (FSBPT) is the agency that writes, reviews and maintains the National Physical Therapy Exam (NPTE) for PTs and PTAs.  They publish resources for PT and PTA candidates, such as the candidate handbook.

There is also a section on exam development, that provides information on how FSBPT decides what to put on the exam.  If you would like to know what percentage of the exam is based on cardiopulmonary or musculoskeletal topics for example, that can be found in the Test Content Outline for the PT or the PTA version of the exam.