See the guide Citing Your Sources on how to avoid plagiarism.
Guide to MLA, APA and Chicago style guides.
MLA Handbook (9th edition, 2021)
MLA Handbook Online
EndNote is a program that makes it possible to collect and organize references in a database and instantly create properly formatted bibliographies.
Zotero helps you collect, manage, and cite research sources. Zotero allows you to attach PDFs, notes and images to your citations, organize them into collections for different projects, and create bibliographies using Word or Open Office.