In the last 6 months I've interviewed for both an apprenticeship (business admin) and a full time role in a HR dept for a local authority.
The HR interview was much more in-depth than that apprenticeship one, which I imagine will be the same for you. The requirements for an apprentice are not the same as expected of someone in a more 'qualified' role so I shouldn't imagine it will be too heavy
I had to fill in a booklet when I first got there that contained a few questions. Can't remember them all but one asked what I knew about the company, another asked for an example of good customer service that I'd given.
I can't remember the interview questions exactly, but I was in with 2 women and they were very reassuring that yes it was an interview but to try and relax and think of it as a 'formal chat'
They asked me why I wanted the role, what I could bring to it, if I was aware of the wage, and why I was considering leaving a full time role for an apprenticeship. I think I was also asked my strengths and weaknesses.
Have a google of most popular interview questions and go through them all yourself. I done that for my last interview and felt really prepared going in