If there is an editor instead of an author, insert the editor's name in the place of the author's, followed by (Ed.) or (Eds.) for more than one editor. If you are referring to a chapter by another author within an edited book refer to the section 'Chapter in an edited book'.
See also the APA's guidance at: https://apastyle.apa.org/style-grammar-guidelines/references/examples/book-references#2
Smith, J. A. (Ed.). (2008). Qualitative psychology: A practical guide to research methods. Sage.
Editor Surname, Initial(s). (Ed.). (Year). Book title: Subtitle. Publisher. DOI (if there is one)