In short, a CPA is a higher designation in the accounting field. Where an accountant has achieved a bachelor’s degree, the CPA (Chartered Professional Accountant) is a designation earned after completing specific educational and work requirements, and passing an exam.
CPAs can conduct all the tasks that are done by accountants, but an accountant cannot conduct all the tasks of a CPA.
Freshbooks has an amazing article which goes into more detail about the differences between a CPA and and accountant.