Biblatex APA citation with parentheses

For real APA citations you want to use the package biblatex-apa (7th-edition APA style) or biblatex-apa6 (6th-edition APA style).

With biblatex-apa use style=apa,. With biblatex-apa6 you'd use style=apa6, in the example below.

documentclass[american]{article}
usepackage[T1]{fontenc}
usepackage{babel}
usepackage{csquotes}

usepackage[backend=biber, style=apa]{biblatex}

addbibresource{biblatex-examples.bib}

begin{document}
Lorem autocite{sigfridsson}
ipsum parencite{worman}
It was shown by textcite{nussbaum} that

printbibliography
end{document}

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If you just want author-year citations and not necessarily all that APA style entails (some people call this class of styles "Harvard style"), you can use the standard authoryear style and customise it to your liking (Guidelines for customizing biblatex styles).

documentclass[american]{article}
usepackage[T1]{fontenc}
usepackage{babel}
usepackage{csquotes}

usepackage[backend=biber, style=authoryear]{biblatex}

addbibresource{biblatex-examples.bib}

begin{document}
Lorem autocite{sigfridsson}
ipsum parencite{worman}
It was shown by textcite{nussbaum} that

printbibliography
end{document}

---

Independent of the exact details of the style, most biblatex styles print citations in parentheses if you use parencite. Often it is preferable to use autocite and configure it to produce citations in parentheses (this is usually the default for author-year styles).

Apart from autocite and parencite many biblatex styles define textcite, which comes in handy in case you want to mention the author in your sentence.