What is the function of the 'App Store' on iOS devices?

The function of the 'App Store' on iOS devices is primarily to download and install applications. This platform serves as the central hub for users to browse, purchase, and acquire a wide variety of applications for their devices. Users can search for specific apps, explore categories, and view featured apps, making it easy to find new applications that meet their needs or interests.

While the App Store does provide additional features such as viewing app reviews and ratings, the core purpose is focused on facilitating the installation of apps. It includes detailed information about apps, screenshots, and reviews that help users make informed decisions before downloading. However, these features are secondary to the primary function of enabling the acquisition of software for the device.

Moreover, managing backups of applications or deleting unused applications is handled through different system functions and settings within iOS. Hence, the paramount role of the App Store in downloading and installing apps distinguishes it as the correct answer in this context.