The interviewer will typically ask this question early in an interview to see which recruiting method or platform being used is the most effective. When the employer understands what is working vs. what isn't, they can adjust and change to use the most effective method for their recruiting. If you found out about the job from a friend that already works in the facility, and you know they are a good worker, feel free to name drop. Getting a job isn't all about qualifications but who you know.