The "What to Buy" application is a productivity tool designed for iPhone users to streamline their grocery shopping experience. This app allows users to create shopping lists quickly, utilizing both keyboard input and advanced predictive voice input powered by machine learning. Users can simply dictate their needs, such as "Cucumbers 2 kilograms," and the app intelligently categorizes the item while selecting the appropriate unit and quantity.

Key features of the app include the ability to maintain multiple shopping lists, facilitate quick entry of goods, and utilize smart voice input for hands-free list creation. Users can also share their lists with friends and invite others to edit them with a Pro-subscription. The app supports both light and dark themes and offers cloud storage for lists, enhancing accessibility and collaboration. While the app is free to use, it offers a Pro-subscription for additional features, with various pricing options available.