This document provides guidelines for using headings in APA style. It explains that section headings use level one format, subsections use level two format, and subsections of subsections use level three format. The introduction section does not receive a heading. Level 1 and 2 headings are always on a separate line, while level 3, 4, and 5 headings may be on a separate line or at the beginning of a paragraph. Headings are not indicated by letters or numbers.