What is a search engine primarily designed to do?

A search engine is primarily designed to help a user search for information on the Internet. It functions by indexing vast amounts of web content and then retrieves relevant results based on the user's queries. When a user inputs keywords or phrases, the search engine processes that query and utilizes its algorithms to determine the most relevant pages available on the web. This process often includes ranking the results based on various factors such as relevance and authority, ensuring that the most pertinent information is readily accessible to the user.

The other options involve different functionalities that do not align with the primary purpose of a search engine. Hosting web applications pertains to providing server space and resources for applications to run online, while automating web design relates to tools or software that assist in creating and managing website layouts. File transfer services involve the movement of files between computers, which is distinct from the purpose of cataloging and retrieving information as a search engine does.