It completely depends on the PI, if you're trying to work in the research field. They will more than likely contact you directly through email and set up a 1:1. If it's a staff job, this is usually pretty casual. They just want to make sure you're not inept and you're excited about the position. They'll also show you around the lab and introduce you to everyone who studies/works there. Their approval is important, as well. Make sure you ask a lot of questions about the position; a lot of times the job description will be very different from what you will actually end up doing.

2 in person interviews with Department of Pediatrics. First was with 2 Study managers which were both lacking any social skills. 1 had her hands on her face resting her elbows on the table like she was bored with my interview. The other was asking all the questions in a distracting monotone voice. I was then called a week later in the evening to schedule a 2nd interview. Who calls at 6pm to schedule interviews??? I came back for a 2nd interview, I checked in the front desk with a woman who was yelling at another staff over the phone regarding supply orders. I go in the same conference room with 2 other study coordinators who asked the same questions yet failed to write any information down on paper. I left the interview completely confused on the lack of professionalism from this department. I received a call 2 mo later if I was still interested in the position.