Sadaqah is a donation app where users can create and donate to campaigns. Features include campaign management, fund withdrawals, PDF generation for thank-you notes and invoices, and Stripe integration for payments. Users receive welcome emails on sign-up, thank-you emails when donating, and notifications for donations to their campaigns. An admin panel built with Filament allows administrators to manage the app, including user payments and notifications. The app also features an internal notification system to keep users updated on important activities and events.