Exciting! A little daunting too probably.
Incoming, so she is already accepted and going to be starting school?
When my dad first took me to visit Michigan State University, we walked through campus, and it was so beautiful. Later we went to eat at one of the local restaurants across from campus and he struck up a conversation with a waitress, it wasn’t very busy in the restaurant luckily. He asked her if there were bars to go dancing. LOL. He knew I loved to go out and dance. I was embarrassed he asked such a question, but it turned out while I was a student at State I went out dancing a lot at the bar she mentioned that day. My point is, finding out about fun things she likes to do can be part of your exploration of what is available on campus.
The school will tell her what is required for her studies. Hopefully, the school requires some electives not related to her major. I would encourage her to explore new subjects. My dad did this, and I wish I had listened more. Luckily, my school required some unrelated coursework, but I wish I had tried more classes in more majors, I might have changed majors or double majored. In a smaller school there might be less opportunity, I don’t know how small the school is that she will be attending.
She should come ready to listen and take notes. I would assume the school will be providing a lot of information to help her get oriented.
Make sure she knows how to sign up for classes; when, how, where, etc. Popular classes might fill up fast. Let her know all new students are in the same boat and it’s common to feel a little lost. My mom stayed in town over night, I was out of state, so it wasn’t like she dropped me off and an hour later she was gone. I still felt uneasy though.
She might need to learn some lingo. Like the word syllabus is used in college, but I don’t think it is used in most K-12. She will be given a syllabus for each class with everything that will be required during the semester. She can get a head start on the reading if she wants to. She will need to show up the first day of class with all the text books required. If she hears terms she is unfamiliar with she can google or ask, but she should not feel bad or intimidated, most new students have a learning curve as they get adjusted to college life.
I think @janbb gave a great list in her first answer. Hopefully, the school tells you a lot of those things without having to ask. She maybe can get a job in the school library, but I would hold off assuming it is not necessary for her to make money right away. Plus, working in another place might be interesting to learn other skills too.