Headings are an important way to alert readers about changes in topics or sub-topics in your paper. APA style allows for five levels of headers:
Level 1: Centered, Boldface, Uppercase and Lowercase Heading
Level 2: Flush Left, Boldface, Uppercase and Lowercase Heading
Level 3: Indented, boldface, lowercase paragraph heading ending with a period.
Level 4: Indented, boldface, italicized, lowercase paragraph heading ending with a period.
Level 5: Indented, italicized, lowercase paragraph heading ending with a period.