Using a citation in a research paper means acknowledging the source of information or ideas you've included in your work. It's a way of giving credit to the original authors and preventing plagiarism. Citations also allow readers to verify your information and explore the sources you've used for further research.
Essentially, a citation provides a traceable link between your work and the work of others, showing where you got your information and demonstrating the scholarly integrity of your research. Failing to cite properly is considered academic dishonesty.