What are software libraries primarily used for?

Software libraries serve primarily to provide reusable code and resources for software development. They are collections of prewritten code that developers can use to perform common tasks without having to write the code from scratch. This reuse of code helps increase efficiency in the development process, reduces the likelihood of introducing errors, and enables developers to focus on higher-level functionality rather than low-level functionality.

By encapsulating common functionalities into libraries, developers can streamline the development of applications and reduce duplication of effort. Libraries can include functions, classes, templates, and even higher-level resources, and they often consider best practices and optimizations already vetted by other developers.

In contrast, the options related to storing user data, compiling reports, and enhancing user customization do not align with the primary purpose of libraries. While they may be important aspects of software development and can be functionalities that libraries assist with indirectly, they do not capture the essence of what software libraries are primarily designed to achieve.