Using a free citation management tool can make gathering resources, annotating and note taking, writing and citation in a paper a seamless process saving you time and energy. If you are thinking about grad school, I recommend getting started with one of the following resources:
Zotero - https://www.zotero.org/
Mendeley - https://www.mendeley.com/
Both Zotero and Mendeley have pros and cons. I'm happy to discuss the finer points of distinction and help you get started with either system. Feel free to make an appointment or email me to get further help.
A word of caution, don't implicitly trust a citation manager to do the entire citation process for you. Proofreading your citations is highly recommended as is checking your imports for missing data upon article ingest to your citation management system. Citation managers can only output information at high quality if it's given high quality information
Read more on this topic: Using Citation Managers Responsibly