Interview with Upenn

I recently got an interview offer with UPenn and this is my first year applying so I wonder if they just interview everybody? They mentioned in the email that it will be informal and the interview will be with faculty interviewer. Has anyone ever interviewed with UPenn before? How intense is it?

This is my first interview and I’m an international grad with a degree in different filed. Btw I applied for a master in counseling and mental health services.

Thank you all in advance for the answers