Just as heading structure alerts readers to the order of ideas in a paper, lists help readers understand a related set of key points within a sentence or paragraph.
When writing a list, ensure all items are syntactically and conceptually parallel. For example, all items might be nouns or all items might be phrases that begin with a verb. Most lists are simple lists, in which commas (or semicolons in the case of lists in which items contain commas) are used between items, including before the final item (see more information and examples on the lettered lists page). To draw additional attention to items, APA Style also supports the use of lettered lists, numbered lists, and bulleted lists.
When writers follow guidelines for the creation of lists, their papers become more consistent and readable.
Lists are covered in Chapter 6 of the APA Publication Manual, Seventh Edition
Additional resources

Journal Article Reporting Standards
Guidelines for effective communication of behavioral science research