Mobile app for NGO

My NGO needs an app that is available on both Android and iOS devices. This app will have powerful login/registration functionality, to ensure the security of user information. Additionally, we need it to have donation tracking functionality, so we can keep track of donations and offers in real-time. Furthermore, the app should have a simple calendar scheduling function that allows us to effectively plan out events and make sure we are available for participants. These features should give us the ability to properly manage our charity and stay ahead. The app should provide - The information about the Trustees, work, partners, news etc. - A chat platform for the members