To pick up on one of HK's points in an indirect way, many universities here are applied to using the "common app" .
https://www.commonapp.org
Since the universities expect the students to be solely responsible for all aspects of the applications, the email the student lists there is the ONLY email that many of the universities will send things to. In our experience, only financial info came to the email address listed for parents. I'd recommend using a shared email as the main email if you are going to be actively involved in the process.

So far, most unis send both a snail mail and an email for acceptances. For financial aid we've been getting mostly snail mail.

Just so it has been said: Medical School and other professional schools are generally applied to after 3-4 years of undergraduate studies. There are some "direct admission" programs for medical school that are usually called BS/MD programs that are applied to while in high school.

Wacky fact: Repeating courses at university for a better grade may or may not be a good option at your university. Each university sets their own policy. Some completely erase the first grade, some show both grades, some let you take it up to 5 times, it all varies.

Wacky fact #2: At many universities the student is the one that keeps track of whether they are on course to graduate. The advisor may or may not be involved, let alone interested.

Wacky fact #3: At the top tier research university where I am now, undergraduates frequently have to wait until senior year to take genetics due to lack of class space. It is my understanding that this problem is common for many departments and classes at many unis as well as community colleges. This is why students with AP credit (and thus higher class standing) have an advantage.

I am now compelled to share:
Wacky fact #4: Registration for classes is frequently, but not always, by class. Seniors first, then Juniors, then Sophmores and so on. If your DC have tons of AP or IB credits they may be able to register for their first year classes with the Juniors.