Harvard is an author-date referencing style.
Harvard style requirements
In-text citations
In Harvard, you reference by providing a citation in the body of your text (in-text citation), which includes the author, date and the page number where you found the citation separated by a colon.
Reference list
You then add the related entry in the reference list on a separate page at the end of your document. The reference list entry (author, date, title and source) provides the full details of the reference.
Example
In-text citations
When the bell rang, the children knew that it was time for tea (Jones 2023: 21).
Reference list
Jones, B. 2023. Surviving teatime. New York: Bloomsday Books.