RecruitingClinical trialComparing Mobile Health Strategies to Improve Pre-exposure Prophylaxis Use (PrEP) for HIV PreventionThe purpose of this study is to compare the effectiveness of two mobile health technologies (text messaging or a mobile app) designed to help people take HIV pre-exposure prophylaxis (PrEP) as directed by the clinic. PrEP is the use of a daily anti-HIV medications by HIV-negative people to help prevent HIV infection.