hugo/docs/content/en/methods/page/_common/output-format-definition.md

Hugo generates one or more files per page when building a site. For example, when rendering home, section, taxonomy, and term pages, Hugo generates an HTML file and an RSS file. Both HTML and RSS are built-in output formats. Create multiple output formats, and control generation based on page kind, or by enabling one or more output formats for one or more pages. See details.