Use quotes and sources correctly

I am writing [ACADEMIC WORK] and have doubts about citations. Help me understand: when to quote directly vs. when to paraphrase, how to cite correctly in [ABNT/APA/etc.] format, how to avoid plagiarism, and how to integrate the source into my text without breaking flow. Give examples of direct quotes, paraphrases, and references. Goal: use sources with correctness and academic ethics.