Freemarker is a powerful template engine used for generating text output based on templates. It is primarily used in Java applications to create dynamic web pages, emails, and other text-based formats. By separating the presentation layer from the business logic, Freemarker allows developers to maintain cleaner code and improve the overall structure of their applications. The syntax of Freemarker is simple and intuitive, making it easy for developers to create templates. It uses curly braces to denote variables and expressions, enabling users to insert dynamic content seamlessly. This flexibility makes Freemarker a popular choice for projects that require customizable and maintainable output generation.