Psychotherapy is a subset of psychology. A professor at a university, for instance, may be a psychologist and at the same time not practice psychotherapy.
Some psychologists primarily perform psychological testing and provide little or no psychotherapy.
Nevertheless, most psychologists do practice psychotherapy. Many professionals are allowed to offer a wide range of psychotherapeutic services. Registered interns must also disclose the name and license number of their supervisor. Psychotherapy is no longer a luxury for a select few people. Individuals from extremely varied walks of life find psychotherapy useful for many reasons.