A to-do app solves the problem of keeping track of tasks and staying organized. With so many responsibilities and distractions in our daily lives, it's easy to forget or overlook important tasks. A to-do app provides a centralized location for users to input and manage their tasks, set reminders, prioritize items, and track progress. This can help users stay on top of their to-do lists and feel more in control of their daily activities, leading to increased productivity and reduced stress.