山下美月メッセージ is a lifestyle Android app developed by Sony Music Solutions Inc. This app offers a platform for fans to receive exclusive messages from Mizuki Yamashita, including text, photos, and videos that are not available elsewhere. Users can also send fan letters to Mizuki Yamashita through the app, ensuring privacy as the letters are not visible to other users. Additionally, users can access Mizuki Yamashita's official website through the app, staying up-to-date with official information. The app offers a subscription-based service for receiving messages from Mizuki Yamashita, with content varying from text to multimedia on a monthly basis for a fee. Sending fan letters through the app incurs a separate fee.