The APA 7th edition provides that classical literature should be cited as a book. If a classical work has numbered parts that are common across editions (i.e. 'canonically' numbered), use these numbers instead of page numbers when referring to a specific part of the work or directly quoting from the work. For plays, the act, scene and line(s) is used.
Other important details to include are the editor and publication details.
In text citation
In Much Ado About Nothing, Don John said, "In the meantime / let me be that I am and seek not to alter me" (Shakespeare, 1623/1995, 1.3.36-37)
Reference list
Shakespeare, W. (1995). Much ado about nothing (B. A. Mowat & P. Werstine, Eds.). Washington Square Press. (Original work published 1623)
