A Psychiatrist is a licensed physician (medical doctor) that specializes in the field of Psychiatry, which focuses on the diagnoses, treatment and prevention of mental, emotional, behavioral disorders, as well as substance use disorders. They can prescribe medications when treatment with medication is necessary and ongoing medication management.
A therapist may be a licensed Psychologist (doctoral level PhD or PsyD), Counselor or Licensed Clinical Social Worker (Master’s level); they receive extensive training in psychotherapy, often referred to as “talk therapy”.
Sometimes the best treatment for a patient may be a combination of both medication(s) and talk therapy; in such instance, a patient can see a psychiatrist for medication management and a psychologist/therapist for psychotherapy.
Both psychiatrists and therapists are able to evaluate an individual to determine whether one or both treatments approaches are necessary, and can make recommendations based on their assessment.
For more info: https://www.psychiatry.org/patients-families/what-is-psychiatry