When citing the Myers-Briggs Type Indicator (MBTI) in APA format, you should include the author or organization, year of publication, title of the test (Myers-Briggs Type Indicator), and the retrieval information if accessed online. For example: Myers, I. B., McCaulley, M. H., Quenk, N. L., & Hammer, A. L. (1998). Myers-Briggs Type Indicator. Retrieved from [URL].