To cite a textbook in APA (7th edition), use this basic pattern: Reference list (at the end of your paper)
Author last name, Initials. (Year). Title of textbook (Edition, if not 1st). Publisher.

Example:
Smith, J. A., & Lee, R. K. (2022). Introduction to psychology (3rd ed.). Academic Press.

In-text citations

  • Parenthetical: (Smith & Lee, 2022, p. 45)
  • Narrative: Smith and Lee (2022) explain that … (p. 45).

If you tell me your textbook’s details (authors, year, edition, publisher), I can format the exact citation for you.