This study aims to test the efficacy of ExerciseRx, a free software platform designed to increase physical activity in people with multiple sclerosis (PwMS). Exercise is crucial for managing MS symptoms and overall health, but approximately 80% of PwMS do not get enough physical activity due to barriers like physical limitations, common MS symptoms, and lack of community exercise facilities. ExerciseRx translates clinically relevant activity data collected by personal smart devices into actionable metrics on a dashboard within the Epic electronic health record, allowing healthcare providers to prescribe and monitor tailored physical activity solutions for their patients. This study will test the effects of ExerciseRx in a sample of inactive PwMS.