There are no qualifications for calling oneself an “accountant.” Someone who performs the most basic accounting functions, such as recording bank deposits or printing payment checks, might use the job description of “accountant.”
A CPA has advanced knowledge and skills, obtained through an educational background, professional experience, passing a comprehensive exam, and getting annual CPE (continuing professional education) credits. The person may or may not need to have a valid state license to practice public accounting.
The qualifications vary among different states. Some states require a Masters Degree, while others require only a baccalaureate. In my own state, someone can’t use the CPA designation unless he/she is licensed; if somebody’s certified (has the education and passed the exam) but not licensed, that person can’t describe himself/herself as a CPA.