Presenting someone else's work as your own is considered plagiarism even if it is done inadvertently.
Honest, ethical, academic work is expected at all levels of higher education. See the Academic Misconduct section of the online Student Handbook published by the UWM Dean of Students Office.
This video demonstrates how to use the Purdue OWL site as well as the "cite" function offered in some of the article databases.
Note: Before using either, make sure to check with your instructor as to whether these tools are allowed.