Study Purpose: This research aims to check if a mobile app can help young people with sickle cell disease (SCD) learn to manage their symptoms better. Sickle cell disease is a blood disorder where red blood cells change shape, causing pain and other issues. About the Study: The study will test the app's effectiveness in improving self-care behaviors. It also looks at how it affects quality of life, readiness to transition to adult care, healthcare use, and pain management. Researchers want to understand what helps or hinders using the app and how different factors influence the outcomes. "mHealth" means mobile health, referring to health services provided through mobile devices. Participation: To join, participants must have SCD documented in their health records, own a mobile device that works with the app, and have internet access. You cannot participate if you plan to move away, switch to adult care soon, have certain cognitive impairments, or don't speak English.

• Study involves using a mobile app to aid in self-care.
• Participants need a compatible mobile device and internet access.
• Cannot join if moving or switching to adult care soon.