Essentially 5 ways in 3 categories:
School leaver
- School leaver through direct entry: you do a medical course from high school that gives you your degree at the end. Admissions based on ATAR, UCAT (University Clinical Admissions Test) and an interview. Takes 5/6 years.
- School leaver through provisional entry: You do an undergraduate degree and then your MD degree, but because of your ATAR or other factors you are guaranteed entry into medicine from the start, provided you keep a certain grade in uni. Notable unis offering this are Unimelb (99.9+) or USyd (99.95). Takes 7 years usually (3 years undergrad + 4 years MD).
Non-standard (5/6 years + however long you spent on your original degree)
- You start a undergraduate degree and keep applying for direct-entry programs. If accepted you just leave the undergrad and switch into the direct entry course. Many direct-entry programs (such as Monash) don't accept non-standard applicants. You can also do this if you've already graduated, but might as well do graduate entry at that point.
Graduate entry (4 years + length of undergrad degree)
- Graduate entry through GAMSAT: You finish an undergraduate degree and sit a 6-hour-long exam called the GAMSAT (Graduate Medical School Admissions Test). Based on undergrad GPA, GAMSAT and interview, you might receive an offer to graduate entry medicine.
- Internal graduate entry: You finish an undergraduate degree, and the same uni that you did it at might offer you a place in medicine based on your undergraduate results. You don't sit the GAMSAT, but you need a really high GPA and interview. Some unis might reserve all or most of their graduate med spots for their own undergrad students. Some unis (e.g. Monash) might reserve a majority of THESE spots for graduates of a certain degree (e.g. Biomedicine).
Direct entry seems really competitive (it's the shortest), but it only takes into account your ATAR, UCAT and interview, which you just focus on for 1-2 years. Graduate entry students need to optimise their GPA for the entire uni degree, plus study for the 6 hour long exam. Although, I'm a direct entry student so I might be biased.
Highly recommend checking out this post for the different entry pathways, it has a really good table (gotta log in to see it though).
